this is both extremely common (especially in athletes past their prime that are often heavier than they were in their prime) and thankfully extremely easy to "fix"
all you have to do is start using a seated calf machine a few times a week and voila no more soleus strains
it's not a problem that will be fixed by stretching, rolling, physio work, etc. but by increasing the peak force your soleus muscles can effectively transmit
to help "make it make sense", consider that the soleus sees the highest impact force out of all of our muscles when running. and this is so whether jogging or sprinting. in fact the impact force when jogging is nearly the same as when sprinting, which is not the case with most of the other muscles.
there is no magic amount of sets and reps to do, but i'll usually do about 3-5 sets of 15-20ish reps, adding weight each set so that the last set only is a maximal effort. when i haven't done the exercise for a while i start back up doing the reps slower and very controlled and then after a few weeks i transition to doing them more explosively once i know the muscle and connective tissue can handle a little more violent workout
this is the holy grail of lifting as a form of injury prevention for athletes in sports where running is utilized. nba players on the backside of their careers would be well served to do this to avoid soleus strains that open them up to achilles injuries.
this is also the reason Cam Levins only has one machine he uses in his resistance routine: the seated calf machine.