Hi John, typically what you're talking about is getting less reliant on the OTAs as you progress into your STR business by directing more stays to your own direct booking site. This helps mitigate risk if your airbnb/vrbo account is cancelled and puts more money in your pocket by eliminating the OTA's service fees.
I'd recommend keeping this as a long term goal and instead focus on the operational stuff around running your STR. Believe me your hands will already be full with that at the beginning.
Start with one OTA, get comfortable then after a month or two on board to the other. Once you're up and running on both, then roll out your direct booking site.
Pick a PMS that has both a channel manager and direct booking site. Ownerrez does both very well. The direct booking site takes no coding skills and is basically a template you can choose. Ownerrez can sync calendars between all 3.
Like others mentioned there are other PMSs that can do this. Just be careful on the direct booking site implementation because some aren't as easy to setup.
As for CRM and collecting emails, StayFi is a good solution. However I hesitate to recommend it unless your property sleeps a lot of people. If it's only 2-4 people I'm not sure if the ROI works out because you can get your primary guest's email via your PMS (depends on the PMS).