I'm on Ubuntu Pro 18.04 LTS with Livepatch extended support until 2028.  I don't have a spare 1TB hard disk to maintain a full copy of the Bitcoin blockchain (which is just going to keep growing in size forever?).  Nor a lot of understanding about how this cryptocurrency actually works.

I am currently deciding on an non-custodial wallet where I have the private keys.  I was thinking Armory would be a good choice, but it seems the project has mostly stopped at v0.96.5 at the end of 2018?

I was able to install it from the GCC 4.9 .deb package (as well as build it and run) and set up my wallet, but there seems to be two runtime issues either way:
1) The system is not creating the ~/.bitcoin directory.   I gather this means the Bitcoin Core is not running, but I didn't notice anything in the install/build/run instructions that I have to manually install a separate package?   
2) Perhaps related, after quitting the program, I can't re-start it.  I get the console error "(ERROR) ArmoryQt.py:5975 - Socket already in use.  Sent CLI args to existing proc."  Re-boot the computer and I can re-start it one time again.

But before going too much further to try to resolve these issues, perhaps it may not be a good idea to choose to start using Armory at this time?  And maybe without enough disk space it is not going to work for me anyway?  Best alternatives seem to me to be Electrum or Coinomi, or is there another suggestion?