Depending on your mixture setting, acetylene/oxygen burns at around ~6000 deg. F., propane/oxygen at around ~4000 deg. F.
A welder potentially can create temperatures from ~9000 to ~36000 deg. F. (5000-20,000° C)
Most welding unless tack welding requires you place an electrode on metal for a significant amount of time. Whereas when using a torch you can scarf metal within a few seconds.
I use to work with a torch, layout and other tools along with production welders on large vessels. Some of the steel required pre-heating in order to create a clean cut. We were working mostly with mild steel and HY-80, some of which was 3 inches thick, the lighter steel being around 1/4" to 1/2"
An acetylene/oxygen torch is going run much cooler than a welder, plus the amount of time with contact to metal is usually significantly less.
Yes I recommend being careful when using a torch around a pressurized tire, however it wouldn't be the same as using a welder. A torch can be used from a few to several seconds. If getting too hot and/or longer periods of time applying heat are required. I would use water too cool down the rim and wheel bearing hub and/or use the torch only for a few second then stop, allowing the metal to cool then restart again.
If you feel uncomfortable with any sort of torch just don't use it. Try another method to remove a lug or nut or have someone who knows about and how to use a torch to scarf out the lug. I recommend trying other methods before using a torch.
I worked once with a torch for years and became very familiar as it was a 40 hour week using various tools and a gas torch. A torch can become a dangerous tool if not used properly.
Years ago we I used to work separately inside different size metal tanks, compartments, double hull areas, etc. I remember once while working by myself in a compartment hearing a bunch of commotion. I put down my tools and shut off my torch, went up to the upper deck and found people pulling one of the workers out of another compartment. It turned out the gas from his torch or hose leaked up inside his coveralls, possibly for a few mins. When a spark hit him he went up in flames, survived but had some very bad skin 3rd degree burns, etc. I can't remember if he ever came back as he was laid up for months. When working with a torch, especially in small compartments you need to double-check for hose and/or torch leaks, making certain your torch is off when it's not burning and in use.