By "sometimes laggy", I mean that it works fine for a minute, then it is choppy for a few minutes, fine for a minute again, then choppy, etc.
I have tried a lot of the already given solutions such as editing the /var/lib/bluetooth/mac-pc/mac-mouse/info
to add the connection parameters and one more similar solutions which edits seperate files.
I also ran a few diagnostics the info is down below.
The main thing i find weird is that when i run bluetooth manager and right click setup the mouse it runs fine for a few seconds before getting slugish again. There is another way to replicate this situation which was using hciconfig scan command in terminal made it run smooth for a few seconds.
$ dmesg | grep -I blue
[ 30.120183] Bluetooth: Core ver 2.22
[ 30.120198] Bluetooth: HCI device and connection manager initialized
[ 30.120201] Bluetooth: HCI socket layer initialized
[ 30.120202] Bluetooth: L2CAP socket layer initialized
[ 30.120204] Bluetooth: SCO socket layer initialized
[ 31.395146] Bluetooth: hci0: BCM: chip id 70
[ 31.396141] Bluetooth: hci0: BCM: features 0x06
[ 31.412156] Bluetooth: hci0: dell-Inspiron-3543
[ 31.416150] Bluetooth: hci0: BCM43142A0 (001.001.011) build 0341
[ 34.019178] Bluetooth: hci0: BCM43142A0 (001.001.011) build 0341
[ 34.035256] Bluetooth: hci0: BCM43142A0 Generic USB Class 2 NonUHE @ 20 MHz
[ 39.041570] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 39.041572] Bluetooth: BNEP filters: protocol multicast
[ 39.041575] Bluetooth: BNEP socket layer initialized
[ 52.617208] Bluetooth: RFCOMM TTY layer initialized
[ 52.617213] Bluetooth: RFCOMM socket layer initialized
[ 52.617217] Bluetooth: RFCOMM ver 1.11
[ 76.147097] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[ 76.147106] Bluetooth: HIDP socket layer initialized
[ 76.150103] input: Bluetooth Mouse M336/M337/M535 Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0002/input/input21
[ 76.150611] input: Bluetooth Mouse M336/M337/M535 Consumer Control as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0002/input/input22
[ 76.150912] input: Bluetooth Mouse M336/M337/M535 Keyboard as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0002/input/input25
[ 76.151558] hid-generic 0005:046D:B016.0002: input,hidraw1: BLUETOOTH HID v12.03 Mouse [Bluetooth Mouse M336/M337/M535] on ac:d1:b8:c3:50:48
[ 1862.205868] input: Bluetooth Mouse M336/M337/M535 Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0003/input/input26
[ 1862.206117] input: Bluetooth Mouse M336/M337/M535 Consumer Control as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0003/input/input27
[ 1862.206250] input: Bluetooth Mouse M336/M337/M535 Keyboard as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0003/input/input30
[ 1862.206567] hid-generic 0005:046D:B016.0003: input,hidraw1: BLUETOOTH HID v12.03 Mouse [Bluetooth Mouse M336/M337/M535] on ac:d1:b8:c3:50:48
[ 1983.198141] input: Bluetooth Mouse M336/M337/M535 Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0004/input/input31
[ 1983.198493] input: Bluetooth Mouse M336/M337/M535 Consumer Control as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0004/input/input32
[ 1983.198698] input: Bluetooth Mouse M336/M337/M535 Keyboard as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0004/input/input35
[ 1983.199155] hid-generic 0005:046D:B016.0004: input,hidraw1: BLUETOOTH HID v12.03 Mouse [Bluetooth Mouse M336/M337/M535] on ac:d1:b8:c3:50:48
[11971.835681] input: Bluetooth Mouse M336/M337/M535 Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0005/input/input36
[11971.836087] input: Bluetooth Mouse M336/M337/M535 Consumer Control as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0005/input/input37
[11971.836309] input: Bluetooth Mouse M336/M337/M535 Keyboard as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0005/input/input40
[11971.836838] hid-generic 0005:046D:B016.0005: input,hidraw1: BLUETOOTH HID v12.03 Mouse [Bluetooth Mouse M336/M337/M535] on ac:d1:b8:c3:50:48
[12319.290163] input: Bluetooth Mouse M336/M337/M535 Mouse as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0006/input/input41
[12319.290374] input: Bluetooth Mouse M336/M337/M535 Consumer Control as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0006/input/input42
[12319.290469] input: Bluetooth Mouse M336/M337/M535 Keyboard as /devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.6/1-1.6:1.0/bluetooth/hci0/hci0:11/0005:046D:B016.0006/input/input45
[12319.290724] hid-generic 0005:046D:B016.0006: input,hidraw1: BLUETOOTH HID v12.03 Mouse [Bluetooth Mouse M336/M337/M535] on ac:d1:b8:c3:50:48
$ sudo service bluetooth status
bluetooth.service - Bluetooth service
Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2021-03-02 10:40:40 IST; 24min ago
Docs: man:bluetoothd(8)
Main PID: 8765 (bluetoothd)
Status: "Running"
Tasks: 1 (limit: 9385)
Memory: 1.2M
CGroup: /system.slice/bluetooth.service
└─8765 /usr/lib/bluetooth/bluetoothd
Mar 02 10:40:40 dell-Inspiron-3543 systemd[1]: Starting Bluetooth service...
Mar 02 10:40:40 dell-Inspiron-3543 bluetoothd[8765]: Bluetooth daemon 5.53
Mar 02 10:40:40 dell-Inspiron-3543 systemd[1]: Started Bluetooth service.
Mar 02 10:40:40 dell-Inspiron-3543 bluetoothd[8765]: Starting SDP server
Mar 02 10:40:40 dell-Inspiron-3543 bluetoothd[8765]: Bluetooth management interface 1.14 initialized
Mar 02 10:40:40 dell-Inspiron-3543 bluetoothd[8765]: Endpoint registered: sender=:1.34 path=/MediaEndpoint/A2DPSink/sbc
Mar 02 10:40:40 dell-Inspiron-3543 bluetoothd[8765]: Endpoint registered: sender=:1.34 path=/MediaEndpoint/A2DPSource/sbc
$ hciconfig scan
hci0: Type: Primary Bus: USB
BD Address: AC:D1:B8:C3:50:48 ACL MTU: 1021:8 SCO MTU: 64:1
UP RUNNING PSCAN ISCAN
RX bytes:1217978 acl:71784 sco:0 events:6538 errors:0
TX bytes:85561 acl:61 sco:0 commands:5974 errors:0