No problem getting certificate of residence if the hotel filed the tm30, but a lot of banks want a yellow house book, lease agreement or work permit, to open accounts... Started back in 2018
For example, I've been paying my pension into my Thai account for 3 years and now that I want to switch to retirement visa based on monthly income, my local immigration office won't accept bank statements, they insist on a proof of income certificate from the British Embassy... British embassy only do tea parties, so this certificate is unobtainable... Hence I need an agent...
You are supposed to to have proof of income, into a thai account, for 12 months, before it can be used for conversions or extensions. Weather or not it will be accepted, depends on the immigration officer
I did it on visa exempt entry, but there's some risk, because it can take upto 8 weeks.
Be safer and faster to do direct at VFS global. Mine took 2 weeks processing then a weeks postage using an agent. The agents are basically doing the leg work, submitting and collecting from VFS global