If it were me, I’d grab an Expert Sleepers solution to keep everything synced, or something similar.
Why?
You already have a modular system going, so an Expert Sleepers setup would probably be within your scope of experience and budget.
You have a lot of nice gear with sequencers - at least 4 in view here, not counting modular and Ableton itself. You like all machines playing at once. Ableton is not known for good sync with external gear. If it was just a single device like an Analog Four, and not used for beats, you might could get away with just OB or MIDI sync to Ableton and not mind it slightly out of sync. But, if you’re using all those sequencers and have beat-based machines like Rytm and Tempest, might as well pony up for a third party solution like Expert Sleepers or SyncGen Innerclock, etc…
I have a Rytm, Ableton, and Push 2. I still have not found a way to get the Rytm reliably in sync with extra beats I have made in Ableton (I use Microtonic, Simpler, etc.). If I were just using Ableton for beats, or just using Rytm for beats, then it might not matter. But yeah, the lack of sync between Ableton beats and Rytm beats is noticeable and irritating. Ultimately, I have to put up with things out of sync while composing, then record Rytm to audio, chop it to sync to get things sounding right. It’s a pain, but cheaper than sync systems.
If you find a solution that works for you, please come back and update this post!