This is really a great work, thanks.
I've tested it on my own
Ubuntu Mate arm64 image on RPi4 with 4GB and it works perfectly. I've imported couple of my (quite large) C/C++ projects, and all was working without any issue.
I've tested it also on Odroid C2
(Armbian Ubuntu 20.04), which only has 2GB
of RAM, and it is quite usable. 1.6GB was used during indexing of the large project, but it finished successfully as well as the project build (with some swapping, so the speed was not great).
I hope you will continue to work on this project and I fully agree with your statement
And ultimate goal would be to get Eclipse Foundation to once again adopt aarch64 for good and have those builds done along with other builds