Get the green tape it works better and do not load your brush with paint 2 thinner coats are better than one thick one.

Ah thank you so much! I will go get the green tape and watch the amount of paint I put on my brush.

Also, once you've stuck the tape down, run your fingernail along the edge of it to really seal it against the wood flooring prior to starting to paint. Sometimes this is called "burnishing".

Also a razor blade will take up that paint for you...proceed with care so as not to gouge the flooring but especially if it is still fresh, it should come up pretty easily for you.

The green is frog tape and it is better than the blue. I have also had very good results on walls for the door trim, using the yellow frog tape. It is gentler on painted surfaces, than the green.

You are using a straight brush that is overloaded with paint. Two coats is standard for a reason. You don’t try to cover it all in a single thick coat and rely on a tape bond to fix that error. Even if the bond holds, the edge will look like krap when you go to peel. Because there will be too much paint puddled there.

A skilled painter won’t use tape. It’s completely unnecessary. They will cut in with an angled sash brush, and possibly a paint shield in awkward areas. I’ve never used tape in my life for straight trim.

Hire a painter. Or develop better technique through a lot more practice.

Frog tape. Works beautifully.

Al of the above. And remove the tape when the paint is still soft.