Make your horse “hot off your leg”. Jane Savoie did a clinic on it awhile back and I’m sure if you google it, you can find the method. It’s very helpful.
Body bandage x https://riding.zandona.net/australia/featured-au/superior-chafe-guard-evo.html
Try switching bits maybe that will solve your problem? Just a suggestion
Rolling ball Spurs or equifit makes these belly guard things that work really well
Definetly get a rolling ball spur!!!
Try to ride without spurs on "non-important " days, so you can actually take your time and work with the horse to get his feeling back a little bit. It helps to give him unexpected command to go trot or canter, so you just walking around with a bit loose reins and suddenly push him to go forward and then trot a small bit, pat him and repeat as many times as you can:) but be careful though, because horses get sensitive to the legs from that exercise, so when you put on your spurs he may be a bit fresh at some point
I use spurs myself so in no way am I 'anti-spurs' but you shouldn't be using spurs to get a horse moving. They're designed to be used for refining and precision rather than just 'go'. If I were you I would take the spurs off, find a buddy to help you and do some sensitising.
Best exercise I find for this is while you are riding, have someone on the ground with a long whip or lunge whip (don't worry they're not going to be beaten!). Go forward to halt, hang your legs completely so your lower leg isn't touching, then say aloud to your buddy with the whip "3, 2, 1" and then tap your horse with your heels and at the same time your buddy cracks the whip, depending on your horse's sensitivity to whips, about 1-2m behind your horse (get them to stand as far to the side as possible in case of flying feet).
Ideally you want your horse to dart forward into at least a trot, not bolt and bronc off haha but not just slowly jog forward either, and if they do jump forward really praise them, then bring them back to halt and repeat. Be careful not to catch them in the mouth as this will confuse and deter them from going forward. Slowly get your buddy to delay their reaction time and you'll hopefully find that your horse starts to jump off your leg rather than the whip cracking and if this happens on the next try get your buddy to wait while you just use your leg but if your horse doesn't react like the previous times then get your buddy to crack the whip behind them again otherwise really praise them. Try from walk and trot as well on both reins.
You should find that you only need to do this for about 15 mins, then continue your ride as normal and they should feel more sensitive to your leg. I would do this for a few rides in a row, then only try the exercise again if they're switching off. I've done this exercise to quite a few of my student's horses and they go really well now.
It's not to frighten them, just wake up to your leg. So much better for your horse than having to kick all the time, and much less work for you! As Carl Hester and Charlotte Dujardin says, "lazy horses you need to ride with your legs off, and hot horses you need to ride your legs on". Hope this helps :)
You can try a body bandage or rolling balls as said before. You can also work on some exercises to sensitize him to the leg so you can use your spurs less.
Varying the work is a good idea, as well as doing a lot of transitions and curves during warm-up and real work.
Try spurs with a rolling ball at the end, worked with my pony who had the same problem
Try useing a less harsh spur if it's still affective