DIY eGPU adapter recommendation- Thunderbolt 3 to PCIE

[Napoleon]

I don't have something to plug a GPU into right now and am on a laptop; trying to get my head wrapped around current builds as I get back into the desktop space. I'd like to do a DIY Thunderbolt 3 eGPU if I can make the cost work so I'd have a desktop case/PSU/GPU to plug into my laptop and would wait on the CPU/Mobo/Memory/SSD, seems like those prices are $700+ for gaming setups (R5-5600X or greater performance) vs ~$200 for PCIe3 to TB3 adapters
- eGPU boxes would be more cost effective in the short term but not long term when compares to $100 PSU/$100-250 Case + 200 PCIE, puts DIY eGPU box at $400-550

Does anyone have recommendations for TB3 to PCIE adapters?
- My laptop only had 1 M.2 port and that is my SSD so using for GPU is not an option unless I replased the SATA HDD with SSD and completely reformatted which I would not like to do
- ADT-Link R43SG-TB3 seems to be the only choice
- There seem to be the most options on AliExpress for R43SG-TB3
- I'm debating using this combined with a vertical GPU adapter that fits a case. However, that would be redundant and PCIE 4.0 adapters are in short supply (though I'm not sure 3.0 x16 really bottlenecks even on a full PCIEx16 mobo, and know it won't with TB3/M.2 speeds

Should I look at TB3 to m.2 and then m.2 40GBPS to PCIE riser?