Welcome to the community, @Flightoplankton!
Good question. In general, I would say that it is always best to run the latest version of QIIME 2 so that you can take advantage of the latest features, improved efficiency, bug fixes, etc. For this reason, we generally only support the latest versions of QIIME 2 on this forum, so if you run into a problem the first recommendation will generally be to upgrade before seeking help.
That said, there usually isn’t anything wrong with running an older version unless if you know that is has a significant bug (which is rare and would be reported here and elsewhere). So you should be okay running 2019.1 if that’s what makes you most comfortable for finishing your project.
QIIME 2 versions are generally cross-compatible so you should be able to upgrade and keep working on the same project — just saying in case that’s your concern.
Note you can also install multiple versions of QIIME 2 in parallel as different conda environments… so it is easy to hop between versions if you need.