I don't think there are any real "shortcuts", you will need to put in effort, and it will take time.
It will also require equipment, even if you use an emulator like GNS3 or EVEng it will require a relatively beefy PC with at least 8GB (16GB or more preferred) of RAM. For learning you need to have multiple routers (real or emulated) in a separate lab network "behind" your main ISP router. And I wouldn't choose the RB750Gr3 for your "main router/pppoe server" if you need to support queues and mangling, as those are incompatible with fasttrack. The hex would still be good for lab work, it is just CPU limted with a 2 core processor. The hapax2 would be better, but even it will probably be underpowered. Next step up would be the RB5009 but that's a significant jump in price (based on your choice of RB750Gr3).
I would take what rextended said seriously (the advice about being an ISP and also what to expect with the RB750Gr3 when it is doing everything you want it to do).
What speed are you planning to provide the neighbors?
How do you plan to get internet to your neighbors?
What level of service are they expecting? Will daily outages be acceptable?
Here's a good free resource. https://mikrotikdocs.fyi/ which has ROS v7 topics (supposedly tested), although I just recently found out about the site from this post.
You should spend some time on this forum and read topics that are related to what you want to do. Use google to find topics (it generally works better than the built in forum search functionality)
E.g. starting micro ISP using mikrotik site:mikrotik.com
Better to learn before 20 households are relying on you.