Dude there’s common mistakes that guys in your position make, which most of us guys who’ve been at this a while have made for themselves. I know I did.
The first is fixating on scale weight. I sure did. I had 200lbs as this magic number in my mind that once I hit it everything would be magical. I got up to 200lbs and surpassed it (think I got up to like 210, I can’t remember now), felt pretty good, then ended up having to cut like 20lbs of blubber I’d gained doing everything I could to push my bodyweight up. Now I’m like 20lbs lighter than I was then and people tell me how much bigger I look. Scale weight is just one very small piece of the puzzle.
The other thing is not taking your diet seriously enough. This is by far and away the most important thing you need to work on. Unless you have the genetics of Lee Priest (you don’t) then your diet needs to be absolutely on point or you’ll never get anywhere.
The final thing is using fear of muscle loss as an excuse to rationalise not doing other important stuff. Muscle is nowhere near as fragile as the internet would have you believe. Doing things like running home after work or whatever will not make your body piss its pants and shed muscle.
So yeah, try not to fall into these all-too-common pitfalls people starting out usually do. And you say “I’m determined and that’s all I need” which isn’t really true. You need to be determined, but you also need to be smart or it’ll not get you anywhere.