I spent a lot of time doing Hanon exercises, so that my fingering and technique would improve without having to learn other people’s songs Pet peeve of mine when it comes to instrument lessons!
As someone that’s taken lessons for years as well as taught lessons, I’d recommend the in person lessons. However, I don’t know what the online lessons offer. I believe you need feedback on your lessons, not just to be told what to do, so if you can get that online, I would put them as almost equal. I think starting with a good instructor who can then get into theory with you is a potential plus again for in person lessons, but again I have no idea what you can get from online lessons.
Hanon exercises are a good way to train your fingers.
25 key is way too small, and I’d actually recommend a 61 key over a 49 key if you can afford it. You can get all kinds of cheaper 61 key keyboards used, just make sure there’s some touch sensitivity as I feel that is an important part of expressiveness in playing.
Because I wanted 88 keys some touch sensitivity and it to be stand alone for practices I also hope my daughter may learn with me a but she is just 4 at the moment.
I learned the old fashioned way. I can’t knock any of these on-line, new age methods as I’ve never tried them.
Key thing in learning Piano, or any instrument for that matter is commitment. I used to hate hearing my instructor say “1 Hour a day!!” but now I really understand and appreciate why. By time I started playing guitar I had been playing keys for about 8 years and I excelled quite quickly in my guitar skills.
Nothing beats having a skilled teacher beside you to help you along.
Practice, Practice, Practice.