I did just that on our last 5er, a Titanium and gained at least 4 inches in depth in the bedroom, 2-3 for the rest It was quite a long term project
It's not a super simple job nor particularly inexpensive but a mid level DIYer with a table saw and some wood can do it. I used 3/8" poplar from the local big lumberyard (they don't carry that thickness now). For the deep BR drawers, I needed to glue pieces together using my router table and a bit and some joinery biscuits to get the height. I also used some mid level capacity drawer slides, replacing the usual puny RV junk.
2014 Montana High Country 343RL (Sold!)
2011 Ford 6.7 Lariat CCLB (Went to PU Heaven)
2019 F150SC XLT SE Sport,w/full tow package