Any new Mac will ship with Tahoe, and cannot have an older version of macOS installed.
If you want to avoid Tahoe that badly, then you're going to have to look around for older, new stock that hasn't been sold yet, and shipped with Sequoia.
That still leaves the issue of falling behind. Trying to stick with Sequoia means eventually, the latest third party apps you may rely on simply won't run on what will be an "old" OS.
Safari itself only gets updates through three (or four) major OS releases. After that, it's stuck at whatever security level it was last updated to. The only way to move Safari forward after that is to upgrade the OS.
Third party browsers usually have longer support, but even they eventually get left behind. The Brave browser only supports macOS as far back as Catalina (10.15). You can download older versions, but they will lack security updates, and web updates in general (read, web pages won't load correctly since the old browser will have no knowledge of newer web features).
Same with Firefox (10.14 Mojave). Chrome (macOS 11, Big Sur).
Also, keep in mind this is a complete rewrite of the OS, including the GUI. There are bound to be glitches. Most of which (hopefully) a .1 update will fix.
But regardless of all that, you will eventually have to get used to the new look. Or, that is, you will if you plan on using the web in a way that works as expected, and third-party apps that someday won't run on Sequoia.
Many users also hated the flat look of macOS Yosemite when it came out, much preferring the rounded, 3D look of previous versions. Then people got used to it and stopped complaining. The same will happen with the new glass look.