Brand: no idea and it doesn't really matter.
Observations: The fork looks like steel due to its fine profile and high rake.
Frame has braze-ons for mudguard / fender mounts, (so its a general purpose kind of bike) and both brake and gear cabling stops. This leaves the inner cable exposed for part of its length. There are no pump pegs visible or they've been removed.
Lugged construction with a threaded steerer.
A steeper head tube angle than the seatpost angle.
No fancy derailleur hanger - looks to use a generic claw that slots up the dropout.
Dimpled chainstays for tyre and chainring clearance. Relatively unusual for the period.
There appears to be something missing around the BB - the rear derailleur cable has a stop on the right-side chainstay, but its on top. This suggests the cable runs through a "diverter" that goes above/over the BB, not underneath like more modern bikes. May be a chromed clamp-on part removed for the painting.
Answer I'd say you're looking at a late 80's steel frame with a couple of modern ideas for the time. The fork looks to be older, or at least has nothing new about it. The fork may not be original to the frame.
As for brand - you can call it whatever you like.
An option is to get some decals made/cut that say "Dan's Bike" and put them on before doing the final clearcoats. If you want, you could call it Apollo `23, or Colonagfaux, Time Fauxlon, or "Toyota Corolla" Be creative.
If you choose to name it something that already exists in the bike world consider copyright first.