They’re all hard to start, due to the direct drive hydro pump, but ones with bigger pumps are obviously hardest. You can run a lower viscosity hydro fluid, particularly if you’re only using it in cooler weather, and that should help.
You could also convert it to electric start, as I did with mine a few years back. See if there’s a variant of your engine with electric start option, and either buy the parts required to convert, or just swap engines. If there’s no variant of your engine with electric start, then find a replacement that will fit, based on HP, exhaust location, shaft orientation. Make an electric cord set that allows you to plug it into your tractor for starting, if you want to avoid having to mount a battery on it. I made my cord set out of some cheap jumper cables, cutting off the clamps and replacing with forklift batter connectors (50A).
I did this a few years ago, and thank myself every January, when that big pump is full of cold fluid. I only use the electric for the initial cold start, it’s much easier to pull after warming up.