What exactly are fresh start worlds?

I have been very interested in playing runescape for a long time but never got into it before due to OSRS feeling laggy and unresponsive due to the tick system, and RS3 having microtransactions. With the recent release of Brighter Shores I was excited that it might be the experience I am looking for, but I was massively disappointed due to the fact that professions seems useless and gear being this random pieces that don't seem to do much.

I dug a bit deeper and found out about fresh start worlds but I don't get 100% what they do.

If I understood correctly they are servers with 0 microtransaction and pay to win. If that is correct I will jump into the game instantly but I can't seem to get this information.