I think it really depends on your goals, finances, and talent, but the BL is there’s no way to really squeeze more hours into a day or week.
The best way to meet competetitive goals, as others have said, is to have one, maybe two, horses in full board/training with a great trainer. The horses are kept fit and tuned, and so you can show up for a lesson and go right to work, and meet up at horse shows and have a good chance of success.
Having the resources to do that, however is not cheap. Neither is purchasing the talented, sound, and well trained, ammie-friendly horse that will perform for a rider that has had limited practice time.
If “advancing” doesn’t necessarily require competing, and instead is more along the lines of enjoying the journey, but willing to take some time to get there, it’s more doable.
I get moved to new jobs every few years. When I work long hours in my home state (45-50 hrs/week), I can still progress because I have dedication to ride after a long work day, lights in my arena so I can school before/after work in all seasons, and a trainer who’s willing to fit me in as our schedules allow. I am diligent about doing ‘homework’ and I take copious notes on our performance, with periodic video, so I can track our progress. This works if I already have the skill set and am developing a green or young horse within my comfort levels. If I was trying to learn new skills or advance beyond what Iv’e done in the past, I would need more regular interaction (via lessons and training rides).
Right now I’m working out of state (45-50 hrs/week), so I can only ride weekends. I don’t have the finances to have the horses in full board/training, so I accept that my progress (bringing along my 2 homebreds) will be slower than if they were getting ridden 5-6x/week
Many times I’m working out of country for months at a time (in excess of 80 hrs/week). Other than staying fit myself, and trying to stay motivated by watching videos and training seminars, there’s not much a I can do.
TLDR: So, absent the significant resources to hand off the daily work to someone else (work = daily care, training, fitness work, grooming, etc), you (generic you, not specifically OP) have to temper expectations. Advancement may be in fits and starts depending on a variable work schedule, but the trick is to own an appropriate horse, have the right support structure (trainer and family/spouse), and the dedication to fit in a deliberate/organized ride every single time you can.