Weight / Fat loss

If you want to maintain your fitness, just do whatever gets your heart rate up the most and gets you out of breath. Personally id just go for a run outdoors.

But i'll give you an example of something to try in the gym;

20xAir squats (just squat up and down with your bodyweight)

Swing your arms and legs around to loosen them up. Possibly do some cossack stretches.

Put treadmill on max incline (usually 15) do 3 x 2 minutes as fast as you can. drop to walking pace for rest periods.

Get onto concept rower; use as moderate-high pace for 1 minute, then 3 sprints as fast as you can. Just like the treadmill, cruising speed for rest periods.

Finish with something strength based. Your choice, whatever you feel comfortable with but try not to use a machine. Step ups on a small box with a dumb bell in each hand is a good example for lower body. For upper try some pull ups even if all you can manage is 1 rep. And some traditional push ups.

Aim to progress at rower/treadmill by faster times and shorter rest periods.

Aim to progress as strength work by adding reps or adding weight.