Great advice by @Hamp Lee III
I'd echo what he said. Normally, for a new investor, the best advice is: stick to one type of investment strategy, learn it as best as you can and then take action. I'd still go with that advice generally but, like he mentioned, flexibility in this market is key right now. You can't "napkin math" a property on the market with current price and rents, make an offer and hope to cashflow out the gates. It will take some patience and time at least and likely some creativity and an infusion of some additional equity.
Look hard at the property's zoning. Can you add doors after purchase, etc. Can you rent by room or do one unit as an STR/MTR plus long term rent, etc.
The ADU option is great up front. That being said, what I find challenging is that unless you plan to stay in the property as an owner occupant, that strategy may not help you long term. A use of capital to do that build may just be better used for additional buildings.
Most of your small multi's will be here in the urban core but will be older properties that may need some work, so just keep that in mind.
Keep building out your team and doing your research as you're doing now!