I used to recommend this to one of the other desthority fella. I believe this had a great chance of being BTC dome with slider:
https://www.ebay.co.uk/itm/Vintage-Packard-Bell-Mechanical-Keyboard-5140W-Good-Condition/362911969245?hash=item547f3d2fdd:g:3wMAAOSwy9ZeC49ISo as you can see here, it is btc under the name of packard bell. Expand your search by including that, eventually you would encounter one.
From the wiki, it says btc 51 series should be dome with slider. however as the keyboard you are asking here is the very last of the line (5197) Im not very certain .
By the way, i dont see the hype behind btc dome with slider. Yes, when comparing with rubber keyboard, they are better. But when comparing with mechanical switch, especially the cherry family and alps, they feel meh. You bottom out very hard and the key sucks you in. The snappiness of the slider can't save the keyboard from being a rubber dome. That is my experience.
Now I have never tried topre in my life, so I am definite bias. You may like it. Good luck finding a reasonable one.