Unless you're Disney, you probably don't need (let alone can enforce) trademark protection in literally everything jurisdiction. So start by picking where you want/need your trademark protected. Then look into law firms that specialise in it for those markets (countries or regions).
In many markets (for example EU/EEA and UK), you can do trademark registration online quite easily and affordably. It's well built and easy to get right. While it's almost always a good idea to go through a law firm, you might not need one if you're on a tight budget.
Marcaria has been around for a long time and covers most territories. They used to do incorporations and bank accounts as well once upon a time but stopped that around the time the current era of "offshore" companies began. Not enough margin left and banking got difficult, so they dumped it all and went full focus on trademarks.
Vistra is another multi-regional service provider that does trademark registrations all over the world.
depends on what you need...
for EEA basic trade mark registration (name, logo) you can do it easily on your one - I did myself three time... fat fee is charged of course https://euipo.europa.eu/ohimportal/en/trade-marks