I see no one has talked about your vacuum dilemma.
On one hand, a vacuum is a vacuum. On the other, there are some good reasons some cost more than $500.
The price starts to climb when a better turbine is spec'd, and again when noise attenuation is built in so you don't hear that whine. Add a cartridge filter - more $. HEPA filter - still more $$$. Most of the $500+ vacs have variable suction, which is very useful for sanding. Especially finish sanding. Then there's the tool triggered receptacle. You'll wonder how you lived without one once you've tried it.
Festool takes it further and adds remote control (bluetooth) , an uber premium hose that's supple and smooth, onboard concealed hose storage , and the ability to stack the systainers for storage , transport and just general use. Again , all add $ $ $ to the final cost. Is all that worth it ? That's a conversation as old as..............................
with no answer.
As to you getting a CT26. I'd suggest looking smaller, like a mini/midi. Same performance and features, only the capacity is reduced compared to the 26. Still have plenty of capacity for the hobbyist. I have them for professional install teams and we're not changing the bag every day because it's too small like some may have your believe.
Karcher makes a quiet vac at around $200, but not really in the same league. Lots of guys like Fein, though it's still expensive and has less performance compared to FT.
For an 'adapter" - I'd offer this:
https://www.amazon.com/Cen-Tec-Systems-94192-Universal-Collection/dp/B07NZZZ5ZL/ref=sr_1_31?dchild=1&keywords=powertec+hose&qid=1608390540&sr=8-31Good hose, and it'll allow you to regulate the suction somewhat. Something your other hose / adapter options are not going to do. That Rockler offering looks spiffy at first blush, and the adapters are sweet. However, the hose is terrible, just awful.