Presumably you work or have an office on the peninsula which is why you're ruling East Bay out? If you are remote, Oakland gives you a lot of inventory with great lifestyle (food, accessibility, etc) and a bette price, but the schools are lackluster (although changing).
We did the live-above-tenants thing for a year, and enjoyed it because our tenants were incredible but candidly were ready to move.
You definitely give up on a few things - complete privacy (multi-families are old, with thin walls and creaky floors), sharing a backyard (we never felt comfortable having friends over and having too many beers on weekends or holidays), and we were always in landlord mode mentally (let us know if you need anything! oh wow ok I'll take a look at the dryer etc). Even if your tenants are practically perfect (which ours were!), this dynamic always existed for us - your mileage may vary.
I'm glad I don't have to live above tenants again. I will unlikely live above tenants again unless I need to.
After a 20 second review, there's way more inventory in San Jose than any other part of the Peninsula but there are cute exceptions. The million dollar question (quite literally) is- what are your numbers/budget? Did you purchase your SFH for $1M and it's now $2M and you're hoping to keep PITI around $5k/month after rental income? If so, you could purchase something for $2.2M ($1M down, PITI at 3.1% for $1.1M would be ~$7k/m, rent inlaw unit out for $2k/m so your nut is $5k/m) or purchase something for $2.5M but you'll need at least a 3bed unit (PITI would be closer to $9k/m but if you can rent out a unit for $4k/month, you're good). Here's an example of the latter - https://www.redfin.com/CA/Menl...
Hope this helps! Understanding your budget/numbers would be helpful.