The reproduction mirrors Anglerfish in some ways. which you should look at if it wasn't your inspiration in the first place.
On to the question.
First, there's a SIZE issue.
When it comes to pregnancy, or keeping an animal inside another animal, the size ratio has to be much smaller than the animal keeping it inside.
Babies tend to weigh less than a 10th of what the mothers do in most species. This is just a matter of practicality. I would make your males much smaller than this. Even half the size is an issue for survival. With a baby onboard AND the male, things will be problematic. Because of square cube law, your ladies will weigh considerably more than the males, but the male's height might be an issue and the weight is twice what's easy. (Square cube law says that a 10 foot tall giant would weigh about 1100 and a 12 foot about 1500 pounds. Some males can weigh over 200 pounds at 5-6 feet tall).
Add to that the size and structure of the mouth required. This is not just a matter of gag reflex, it's a matter of being able to breathe and swallow something whole while it is alive. Even if I were ten feet tall, I would have great difficulty swallowing a 5-6 foot tall something--and that's even if I could unhinge my jaw. This part is going to take time.
Movement, after swallowing something half your length will be...difficult and take a considerable amount of time. Going to say they will have to have snakelike characteristics. They may not move at all after this, until they have at least partially digested.
You talk about daily activity, and this is going to depend if they are in or out of the water. In the water, it's going to be nominally easier.
But I would for certain argue for not moving much at all during this process. Internal organs will be squashed from the get-go. It would be like starting at the 9th month of pregnancy. Human women can move around during month nine, but it's hard to bend and what not. This is for an occupant weighing just 6-9 pounds, with an average length of about one and a half feet. Most women weigh anywhere from 100 pounds and up, with an average height of 5 foot 4.
Instead of slowly adjusting to something this large, as we do during pregnancy as baby grows, your fish ladies are going from nothing to everything. This is fiction, so any premise is acceptable, and these are fish ladies, so if you want the males to be this large and for them to swallow those dudes whole, party on, but this is not going to be a small thing to adjust to all at once.
I would make the females even larger than you have already, and make them exclusively in the water, while the males can do both more readily.
The process sounds like it takes a lot of energy, but you have them digesting and respawning their males (unless I am misreading this) on nearly a daily basis.
Pregnancy in people in animals means extra resources and food. If you want a healthy baby. It can rob your bones of calcium. Even with the re-use of the male's essence, they are essentially destroying and reconstituting life, which will take more energy than just the male's form/life force to do. Plus, the ladies have to eat and get food at some point, and the males do, as well, unless the ladies are also providing nutrition for them as well.
My point here is not to say this is impossible (it's your world after all, and can run on magi-biology) but that you should consider the cost--and that females should be completely different in new and fantastic ways. This is not "no big deal, meh, they remake the males"--this is absolutely incredible and should cost something.
Inactivity, having beta females bring all the correct foods for their time (perhaps even capturing males for the larger ladies) could be a cost here. Certain magics could be a cost here. The ladies, over and above being tall, might also be LARGE, and weigh a lot for their height.
On the day to day, they have I guess evolved to be this way, so think about how that would be viable.
You say it takes "hours" for the digestion process, but you say nothing about how long the reconstitution takes. I am going to guess that's it's all together. Maybe have it start when they are low activity, and go through their sleep cycle or something. We sleep for hours a night, and these ladies might as well, which could solve your activity issue.