As has been discussed at length, it sounds like mounts are the key for you. There’s definitely a big difference between riding to work on something you don’t have to think about mounting, and something where the mount may cause big problems.
Not to say I don’t have to think about mounting mine, but I’m not worried about it. I’ve had a 45" big wheel since 1982, so a Coker was never a mounting issue. When I first attempted the 8 mile ride to my work, my knee gave out on the way home (sometimes it wears out from overuse) and it took me a while to build the confidence to do the ride again. I did a lot of bike commutes to get my knees into the swing of longer rides.
Unfortunately my office closed, and now work is at home. My mileage has suffered greatly and my weight has increased.
For mounts, I’m sure there’s been a lot written but I’ll briefly describe how I do it in case there are any differences. I walk several steps to build momentum, and jump up as the pedal is coming up toward rear horizontal. While jumping up the wheel is not moving, but my body continues its forward motion with the intertia that was already there.
The key is getting up there reasonably centered over the wheel. I was very aware of this yesterday as I did lots of starts and stops on a dirt semi-trail with lots of rocks in it, and 125mm cranks. I tried to concentrate carefully on jumping up in line with the bottom of the wheel, so I wouldn’t have to make any big corrections to get going.
Anyway, when you get up there, make sure you don’t stop yourself directly above the wheel. That will make it harder to keep going, especially if you stop a little short (you’ll have to backpedal). You need to get a little ahead of top dead center and start pedaling immediately. At the same time, if you need to make any side corrections these can be done in the form of a little twist to the left or right, just before you start rolling.
As you practice more, it will be easier to tell which direction you need to twist for a smooth start. Also, try to minimize arm motion when you’re practicing. This will help you gauge your improvement. If you can do it without flailing, the control is getting better!
I used to be a motorcycle instructor. One of the most overlooked aspects of safe motorcycle riding is getting the starts and stops down. I would drill my students on those until they got sick of them. If you’re not good at starts and stops, you’re much more likely to drop the bike. You can apply some of this to the 36er, if you want to dedicate some time just to mounts. See how many you can do in a row. Track your progress as a percentage, based on how many successful mounts you make in each 10 attempts. This is a good way to practice dismounts as well, as they’re part of the process.
Last but least, consider your crank length. 125 is great (for me) for relatively flat riding. Now I’m using them on some trails & things, but I’ll still go back to the 140s for the San Francisco tour this fall (steep hills!). If you’re not using 140s or longer, consider trading up, at least until you get the mounts more solid. 150s are great for learning. For me, anything longer is only good for major hills (or multiple knee surgeries).