TM30 is filed by the house owner where you stay. If you plan to arrive on or after May 1st then you and every other foreigner needs to file an online TDAC arrival form.
Anonymous participant recent report of someone getting their DTV in 7 days in Abuja, but no details. use the group search tool Nigeria and maybe msg them.
Milking free visa exempt entry stamps will raise suspicion of living here and not travelling here. You basically asked the same question regarding your Filipino gf 4 months ago, nothing has changed.
Iffy entry scheme if you're new to the freelancer game with no portfolio, don't have tax returns and expect an accountant to magically compose something out of nothing. Suggest you abandon the digital nomad route and apply for soft power. After you get established, if you need to show any ongoing proof you can produce some documentation of your recent endeavor
I had to get my non O retirement cancelled at the Nong Khai border a month ago before they would stamp me out. They sent me to the what I assume was the re-entry permit desk and the lady cancelled my extension ( maybe because she was the only one with the stamp) and sent me back to the IO to get stamped out. I was a bit surprised.