Hot water heater doesnt seem to work well

I don’t know what state you live in at this time of year. The incoming water is much colder than summertime water. Maybe just turn up the water temperature will solve your problem?
Changed the anode today and flushed ours. Despite getting in my head before the job, it was quite easy and straight forward.

I had to cut the old one and had to hang on to the lower piece with vise grips while I cut with my Dewalt 20V sawallView attachment 144301
That old anode was toast Pablo. You may have caught it just in time.