The human mind will create powerful reinforcement to support goals, some will be habits, others will be subconsciously related to that goal. On this forum, lots of guys have goals of easing through high altitudes and endless endurance come whatever hunting season. They build towards that as the end goal, sometimes preparing throughout the year for a singular event.
The issue with that, is that most people don’t stagger or pyramid their training to achieve peak performance walking into whatever event, instead, they flow through a general training program and plateau, and when they plateau, their motivation/habits/discipline take a nosedive.
It’s hard to continue improving on a long time scale without excellent programming for the average person.
One of the best ways to circumvent this issue is to have multiple events throughout the year that mirror, mimic, or support physical movement characteristics of the end event. Running 5k’s (or longer), archery events, shooting competitions, powerlifting events, triathlon races, MTB races, long duration or multi-day hikes…you name it, give you a short term event that supports performance in the long term goal. Find something quarterly, or monthly, that pushes you to be ready to perform.
I arrived at this conclusion a number of years ago and it works for me. Full disclosure, from Thanksgiving to Christmas I pull back on weights and focus on aerobic activity to give the joints a break, and let my diet slide a bit because it’s good for my own personal morale.
The last thing I’ll add is that there is a unique social label being the guy with certain discipline types. I started getting weird looks, side-eye, and off remarks from people when I stop drinking, am on a tight diet, and schedule social events around an event training schedule. It doesn’t bother me, after a while I realized I just had different goals than many people, many of which are my friends, not because I am a super athlete competing for recognition, but because I am willing to park short term wants to be that guy who doesn’t bat an eye when things are going to get difficult on a hunt or in life in general.
Somewhere in your basic motivation that seems to falter at times, is a deeper and more powerful one. You just need to peel back the onion and find it.