Broadly security - it’s possible I’m being a bit overcautious - but as you say better to be that than get tripped up unexpectedly. Hence me not doing regular internet on there, but not seeing the odd Roon software / db update likely being a problem.
The 2 links with 2 routers isn’t changing anytime soon - the only consideration is how I make them work best for me & hence the topic above.
Maybe the simplest solution is easiest. Two completely independent networks; one accessed by a work-provided laptop or PC, and another for your personal use.