Some random thoughts:

1. You didn't specify wireless or wired. It matters. With wired, your biggest problem is going to be getting permission to deploy towers and licensing part of the spectrum;

2. Wired avoids this but adds the problem (and the biggest cost) of the last mile. Where do you run those cables?

a) Poles: you need permission for this and there can be a bunch of hyperlocal laws that will get in your way. For example, you may have to wait for existing telcos to move their wires up or down to make room and they'll take their sweet time.

b) In trenches: you'll need a different kind of permission for this. Local conditions may make this more of less difficult (eg there can be alot of large rocks in the soil).

3. If you run a cable from a house and on a pole or in a trench where does it go? You need some kinf of substation for this depending on the max transmission length of the cables you employ. You need planning permission for that and teh big cost of the real estate required. If it's a hole in the ground, that's less of a problem. If it's a free standing structure containing switching equipment, expect residents to fight it on NIMBY grounds;

4. Depending on where you are you may face local or state laws that restrict your ability to do any of this. Some US states have passed laws against municipal broadband (at the behest of telco lobby). Telcos may have exclusive franchises with certain areas. This has been dismantled somewhat but you may find unofficial opposition anyway;

5. You're going to need installer for all of this and people to handle all the permitting;

6. Once it's built you need people to maintain it. People will come through and cut your wires or they'll be accidents like cheery pickers running through your cables or poles going down in a storm requiring cable repair.

7. Existing telcos are exceptionally good at playing this game and are typically in bed with local politicians who will make your life difficult.

8. Will you get enough customers? Just getting permission to build something will probably lead existing telcos to cut prices and lock in consumers with 12 or 24 month contracts to starve you.

9. Do you have a TV service? If not, you're going to lose a certain number of potential customers who still want this. If you do, the price you pay scales with your size. Verizon, Comcat or AT&T pay a lot less to content providers for their TV packages than you will. Telcos like to bundle TV and Internet so you may find your customers only pay $20/month extra to add Internet to theri TV package.

10. Who do you get upstream Internet connections from? It may well be one of your local competitors. Guess how that goes.

This is a capital intensive business that doesn't reward overbuilds. The only way this can really work is with heavy cooperation from your local municpality. As mentioned there may be legal barries from them doing so (as noted, telcos don't want a repeat of Chattanooga).

This'll work best in low population centers that are underserved or not served at all by existing players. Low density housing means getting trenching permission is going to be less of a problem. Potential customers will also be much more motivated if there other options are HughestNET or DSL.

Starlink probably means even these customers aren't going to be as motivated as they would've been 5-10 years ago.

In more rural areas you may even have the option of microwave relays that'll bypass a spectrum issues and it'll be easier to permission to be a directional wireless tower on someone's boundary.