This topic comes up a couple of times per week. The recommendations are always the same because there simply isn't any new information.
If you want a real scope, the Rigol DS1054Z (unlocked, search for Riglol) is one option and the newer Siglent SDS1202X-E (200 MHz 2 Channel) or SDS1104X-E (100 MHz 4 channel) scopes are another. The 1104 can be unlocked to 200 MHz so it is a really attractive choice.
A logic analyzer can be a bigger help but it assumes that you have all the signals. The scope helps find out whether the lines wiggle at all. Both are necessary at some point.
The Digilent Analog Discovery with the BNC adapter board is another possibility. It works well and it is PC based. It doesn't have near the bandwidth of the Rigol or Siglent offerings. Vintage CPUs don't work at high frequency anyway and I used a 10 MHz scope for years and years. It also has a logic analyzer, a dual channel signal generator, dual channel scope, dual power supplies, pattern generator and so on. I like mine!
A full size scope, like the Tektronix 485, can sit upright on the floor and is easily stored under the bench. That's the way I use mine. All of the 4xx series are luggables, intended for transporting to job sites and used in an upright orientation. It takes a pretty deep bench if they are to be used laying down.
You can't realistically evaluate scopes without driving a stake in the ground on price. I guarantee you, the Keysight $300,000 scope is going to have better specs than the $350 Rigol. The Keysight is probably out of reach for most hobbyists but it does give you an idea of the range of prices. You really do need to get a handle on how much you want to spend. It doesn't have to be a hard limit but if the number is something like $100 then you are looking at used analog scopes of dubious functionality. For $200, you can get a pretty decent used analog scope. For $350 you can get a new Rigol or perhaps Siglent. For $500, you can get something else (maybe) and when you get to the $1000 or $2000 range you should be able to get a very nice scope (but I don't have a recommendation).
For workable entry level scopes, the Rigol or Siglent will do the job.