Is it possible to change the little flat 4 pin plug on my boat trailer to a 7 pin round that will fit directly into my Tacoma? Im tired of going through adapters that get loose and break over time

Yes. You can buy the plug end at Walmart amazon or any parts house hook up the 4 wires from your four flat to the appropriate terminal on the plug and away you go. Plug should come with a schematic to wire it, if you don’t want to any trailer service place could easily handle it. I’m sure YouTube could walk you through it as well.

Green to brown, brown to green , yellow wire to red and white to white

I owned Tacomas for 8 years and the only problem I ever had was with the 7 pin outlet on the truck. I don't need the adapters for my current boat but still use them with other trailers. I tore the OEM outlet off my 2009 Tacoma going through a creek bed. I had much less problems with the $15 replacement. One of the adapters I have has indicator lights for each circuit. It came in handy at times.

This might help, not a bad job to do yourself.

Going through the same issue. 2014 Expedition with a 4 pin connector. Added the 7 pin connector to the vehicle, and plugged in my trailer plug. Turns, brakes and tail lights work but not the backup lights on the trailer which have a brake lockout for backing the trailer I think. Trailer has surge brakes. I went to uhaul to get a wire run from a vehicle back up wire to the plug. uhaul says I need a $200 brake controller and weren't interested in running the wire, Am I right about what I need.

Brake controller

You do not need a brake controller for surge brakes, you need a reverse light wire in your plug to activate the solenoid on the trailer to release the brakes when backing up.

The only wiring difference between a trailer with surge brakes that uses a 5 wire harness and one without that uses a 4 wire harness is the 5th pin for the 12V on the reverse pin, usually taken off the backup light circuit. The 7 pin round can be wired simply using the required pins.
No brake controller is used and I can't imagine why anyone who knows ANYTHING about trailer wiring would say it would be. But then, this is the internet where everything posted is correct.

U Haul just wanted to make some extra bucks. You can just pull a taillight find the wire to the reverse light and use a good inline connector. I did this to run some LEDs pods in my bumper. You might look at installing some LEDs back up bulbs at the same time. Much better light output and lower amp draw. I have 48 watt pods, LED back up bulbs, 72 watt flood/spot combos on my trailer and some lower watt submersibles on the sides of the trailer. I like to be able to see when in reverse. Never had any problems with the circuit but I am not sure if the trailer revere wire is on a separate circuit. The pic is the backup lights that I was running before I went to the pods.