I think the problem is something other than sediment buildup.

I just replaced a15 year old WH that started to leak. I never
drained the WH to flush the sediment (my bad) in the 10 years we've
been in the house. The water in my area is fairly hard & there was a
LOT of sediment in the WH. I Sawzall'd the WH in half for fun (I know
pretty strange)

The WH had a couple of inches of sediment. With 4 people in the house
we never really experienced noticeable loss of performance.

IMO your situation must be preception or some problem other than
sediment? Dip tube?

Don't depend on the cheap plastic drain valve working, when I went to
drain the WH to remove & replace it, the sediment was so deep it
wouldn't drain properly. THe valve failed to shut off completely.
Luckily I had let the WH cool otherwise I'd have been dealing with a
HOT water leak.


cheers
Bob