So I commend you for getting some bloods already.
You can build muscle, feel good, etc. even if you have "lower" test levels than what you think is below optimal. I'd caution mentally screwing yourself by determining you can't get better just because some numbers tell you something (considering you expected them to be 700-800 I'd assume that means you don't necessarily feel crappy).
Now that isn't to say you should not do anything. At this point and given your age lifestyle factors would be the logical first step if you do wish to bump the numbers up or try to improve other outcomes. I'd be wary of anyone who pushes drugs on you at this initial stage.
Hormones can be highly interrelated with so many other aspects (that it can be impossible to fully cover all options of what to do without some sort of viable consult and extra questioning), but a good initial start can be focusing on things like improving sleep (amount and quality), decreasing stress levels, increasing activity (helping shift metabolic processes and things like mitochondrial health into the right direction and shifting body composition, etc.), diet, etc.
Again I just want to stress that you shouldn't stress. Make some changes to improve things (because why not we can all always work to improve in some way), but don't turn it into a huge issue if you don't need to and now you can have at least some sort of baseline to start. I am not a hormone expert so keep that in mind and good luck I hope you find the direction you need and some of the other smarter guys around here can help.