A couple of things, not necessarily related, but to consider, adn YMMV. Moving projects can cause corruption. No two systems are truly identical. This would also explain why copying the contents of the old project to a newly created project on the new system would solve the problem.
This is an often-overlooked troubleshooting step, and it’s easy. Create a new project and copy only the sequence. If it works, the old project is the problem. For extra credit, create a new project AND a new sequence, and copy and paste only the contents of the original sequence. This leaves behind even more, like your track-level effects, but most of these are easy to restore. This solves way more problems than it should, especially if the old project is complicated. And it’s one of the easiest things to try. I believe it’s why Adobe created Productions.
In fact, you could bring the old project into Productions, create a new project, and copy only the latest sequence. Productions will retain all the clip-linking to the original project but allow you to close that old project while you are working.
Do not dismiss “hardware.” This is Windows where “hardware” actually means software, i.e. drivers and supporting files and no two Windows systems are truly identical. Compare your project audio and playback settings and the audio drivers between your systems. Not that this helps you solve the proximate problem.
Also audio can be more of a problem than people realize, especially if the original audio is multi-track and/or not PCM (uncompressed) and/or anything different than your sequence settings, and even worse if you are using multicam. If you have empty audio tracks in your source material, I recommend disabling them at the clip level. Historically, multitrack originals can cause playback issues even if they are not cut into your sequence. I have had projects where I had to transcode my clips just to leave behind the old audio. And you don’t notice the problem immediately, only as the project gets complicated. It tends to be an invisible problem.
Proxies. In my experience, proxies make everything more buggy, not less. When they work, great. When they go bad, ouch. I just had to delete all my proxies in a Project to get it working again. It was easy to diagnose because playback with proxies went to hell, but turning them off was all fine. Turns out, the proxies weren’t helpful. I just ramped back the playback quality. It even looked better.
In general, Premiere has become buggy at the Project level. I’ve had a lot more problems with Projects than with the go-to troubleshooting like cache files.