To directly answer your question, I would go to 19.10 then 20.04. There may be the direct path enabled now that some time has past but I am not sure.
I found this that may be helpful.. I tried "The Debian Way" to get my Ubuntu 19.04 to 19.10 so I could then upgrade to 20.04 following the upgrade path:
In my case I hadn't used this laptop in a while and it got out of date beyond how I can normally upgrade it.
First I replaced archive.ubuntu.com and security.ubuntu.com with old-releases.ubuntu.com then was able to get up updated as much as I could with software updater where the next issue begins.
sudo sed -i 's/archive/old-releases/g' /etc/apt/sources.list
sudo sed -i 's/security/old-releases/g' /etc/apt/sources.list
Software Updater wants to go direct to 20.04 but the distribution updater won't actually do it. You have to be at 19.10 THEN upgrade to 20.04, but this late in the game thats not a straight-forward thing from what I have found.
I then replaced disco with eoan in the /etc/apt/sources.list file and put back archive.ubuntu.com and in the URLs.
sudo sed -i 's/disco/eoan/g' /etc/apt/sources.list
sudo sed -i 's/old-releases/archive/g' /etc/apt/sources.list
(for other Linux builds you will need to use those build names. ALWAYS follow a supported upgrade path)
I then ran
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
Once back online open Terminal again and:
to verify it upgraded. This showed me it was successful.
This got me to 19.10 and now I am upgrading to 20.04 through the Software Updater running the Distribution Upgrade package. I hope this helps someone else.
I saw this question that was sort of unanswered but closed as a duplicate that was EXACTLY my issue but couldn't answer him because his question was closed..
Cannot upgrade from disco 19.04 to focal 20.04 after end of life using do-release-upgrade method
sudo apt-get update && sudo apt-get full-upgradethen again follow the ubuntu blog. I think it should work. I have recently updated from 18.04.3 to 20.04 LTS.