We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Muscle pump from resistance training is caused by the increased blood flow into the muscle to supply needed oxygen. That's why it subsides after a while. It's a sign that you are making a muscle work hard.
For strength-maintenance and strength-building you need to create micro- tears in your muscle fibers. This can sometimes result in muscle soreness for a day or two. It's a good sign of the inflammation needed for muscle repair.
The repair is what builds strength. That's why it's never a bad idea to have a 20-25 gm. protein shake as a meal (we like to make it with a banana) shortly after an hour of resistance exertion. It's also why it's smart to recover for 48 hours or so before pushing heavy weights again. (We advocate "active recovery" days in the form of calisthenics and cardio.)
There is an exception, though, to the 48-hour rule. That is when people separate their resistance days between legs and upper body. That works for some people but I do not like it.
Earlier in the year Joe Rogan interviewed physical polymath Peter Attia MD on his podcast. https://www.youtube.com/watch?v=gP1NA5f4LfE. At about the 1hour and 30 minute point they discuss weight training. Attia describes the physiological issues of weight trying in a very interesting way, including the avoidance of muscle micro tears as a technique to build strength without mass gain, a technique being used to increase running speed of sprinters and distance runners.