Help starting to plan a DIY enclosure

I'm the proud new owner of a baby bearded dragon. He's still very small. I have him in a 20 gallon long at the moment. I've read that I have 3-4 months until he is going to need a bigger more long term solution. From my research I think I want to get away from aquariums and look at my other options.
I'm leaning more towards converting some furniture into a tank for him. My goal is to build one big enough for his whole life. I have two pieces of furniture in my house that might work. I wanted to get ya'lls opinions on the measurements of these two and if they are suitable to my goal of it being big enough for him.
One is a long dresser. Its measurements are-
Depth-15"
Height- 30.5" or about 20" if I want to keep the drawers on top or bottom
Length- 57.5"
SQ/FT- 6

The other is a very very nice wooden baby changing table that I had a hard time getting rid of and didn't want to throw away.
Depth-19"
Height- 29.5" or about 20" if I want to keep the drawers on top or bottom (about the same as top)
Length- 52"
SQ/FT- 7

I'm pretty torn between the two on what will work best for this project, if either of them. I do also know that if I build up or do another level that can add more square feet.
I don't know if this is a bad idea but i'd like to use the top to put my electronics on. My TV will be mounted on the wall above it so no biggie there but maybe have some speakers, roku, and a playstation on top. I believe the concern there would be over heating devices. So it might depend of heat managerment. I have the space between the drawers if they are open. Maybe something to separate the top from my bulbs and such. I'm wanting to use sliding glass from the front so opening up from the top is not a thing at all.

What are ya'lls thoughts? I'm just now planning this and i'll probably be doing it in phases. I've been looking at several DIY's and trying to figure out the best way to do this and not forget anything or misplan.

DIY is the best way to go for large tanks due to cost. It's nice to be able to customize a tank to fit your needs as well. A general minimum size for an adult is 48''x24''x24'' so the changing table would probably work best out of the two. It's good to provide more height if you can to allow for more climbing area and room for lighting. In larger tanks it's worth investing in good T5 UVB lighting which is more effective at larger distances. If you have a fixed top it's nice to have a thermostat to dim the basking light as needed. If you have an open top you can suspend the basking light overhead and raise/lower it to fine tune output. Lots of possibilities with DIY setups. It's worth browsing the DIY and Enclosures sections for some ideas/inspiration.