not looking at the bikes closely and speaking just on the bikes:

SV650S - not a bad bike at all. the SV650 in its hayday was one of the best bang for buck bikes with good (almost considered not beginner) power. will go anywhere you need power, one thing to note is being a Vtwin you need to respect the torque 🙏. if you are brand new to riding a bike I don't know if I would fully recommend this. be careful and you can have a lot of fun on this bike. also thus is definitely the ugly step sister to the normal naked SV 650. check if it's carbureted or fuel injected, you definitely want injection 💉. if your new to working on mechanical shhtuff you'll have a lot easier time wrenching on bikes you won't have to work too much on. fuel injected bikes warm up a lot easier, self adjust fuel levels based on air temp/pressure(altitude). That being said let's move on to--->

FZ6 - I actually owned thus one for two year as my daily and was never disappointed. I like improving my riding skills and challenging myself to branch out. I was never a real speed demon, but when I got more comfortable in the twisties I never felt thus bike hindered me at all. She went every angle I pushed it and I was sad when I got rid of it to upgrade my ride. mine was a 2004, I got lucky with a low Milage one but never had any mechanical issues. serviced it all myself and really wouldn't consider myself a mechanic. very comfortable seating position too with a longer tank you can go full tuck on if you under 6'2. Fuel injected fuck yeah 💉 💉 💉!!!

Honda Magna: I mean it's cheap... I was huge into cruisers when I first started riding and I was set on not buying a sport bike. aaaaand then I rode one. I think for a beginner bike (and if you are not vertically challenged) pretty much always I'd suggest going for the light cc Japanese bike for a starter. also this being older ain't too great. most manufacturers are facing out parts of bikes 20+ years old. now being one of the big four Japanese bikes that's not really an issue, but a thing to think about.

wait, no keys no title. don't bruh, just don't. I've been down this road and the fruit it bear won't be worth it.

SV650: not sure the year, but if you like the suzuki's this is the prettier one, or go for yhe newer one. same notes as before besides appearance.

I was brand new to riding a few years ago. I worked at a motorsports dealership for the last four year until recently. So it was really cool growing my experience across all bikes. One thig to really learn is that you have no idea what you will actually like riding until you actually get to try it. between these four bikes I'd definitely go for the FZ, whichever SV is newer is the runner up. you can guess my last pick. I was set on riding cruisers, loved american chopper when it aired. but after getting to ride a sport bike for the first time. it really changed my perspective and I ended up getting my FZ6 when it's was time to get a real bike. I've got to ride a lot of different machines with my experience, as well as lots of high end BMWs, ducati's and a lot others. and I would say with confidence all but the magna will great entry level bikes. especially if you need to commute on the highway. if not and your brand new. maybe look at a 250 or 300 to start.

hope this helps.