I don't know if 12x is enough for you, but I bought this for my wife to bird watch with. It focuses down to about 5 yards and I can can see pellet holes at 30 yards with it.Viajero 12X50 Monocular Telescope, High Power Monocular with Smartphone Holder & Tripod, Waterproof Zoom Telescope, BAK4 Prism Dual Focus for Hunting Bird Watching https://a.co/d/bqvecmy
Someone here on GTA previously suggested using a baby monitor. I found one that was no longer needed, so free!I like it.Hunter
It's two pieces; there is a TV camera with a wireless transmitter built-in. Then there is a 5 to 7 inch display. Mine run on 5 volt supplies so I don't need A/C power at the range. I haven't used it past 55 yards.Hunter
The phone holder is a simple bracket that holds the phone and attaches to the eyepiece of the scope. I'm almost positive it will fit your s8, if you have the phone in a case you may have to remove it. I have a fancier version for my spotting scope and it works fine (without the case)
Or something like this for a laptop or pc