I took lessons for about a year - 30 minutes per week in school terms over a year, so about 15 hours. My teacher took me from being unable to sing to being able to front a pub band which got decent audience reaction and re-bookings.
She taught me a bit of technique - having a solid support from the diaphragm, holding notes for the full length, hitting a note square on and becoming used to intervals. We also would spend some time working through songs I'd be performing where she'd point out where I was making errors. She also helped me control chest & head voice and helped me with higher notes adding seven semitones, so now on a good day I have a 2 octave range. At the school I went to one lady taught singers mostly for pop / rock / musical theatre. The other taught more along classical & choral lines. All in past tense as I caught covid a second time and within a couple of weeks I had a dairy allergy which has taken most of this year to figure out. I'm hopefully retuning to lessons next year.
I have found the voice is a delicate thing. It's not like a bass guitar that can be played for 2 hours then chucked in a bag until the next a gig. I can't sing for 2x45 minutes like I did last night and expect to sing again today - though hopefully that will come with time and better technique. I seem to have had more colds since I started singing, though I think it's actually that because colds have such an effect, I notice them more.