With some bots back on Nauvis, you can absolutely troubleshoot and even/improve fix stuff from other planets.

Of course, fortifications are important, and you should make sure you've got your factory fairly protected first

Without spoiling anything, all of the planets have different challenges that require different solutions to make stable. Definitely part of the fun is that you can't copy/paste solutions between the planets

Just make sure you have decent roboport coverage on your nauvis base and plenty of bots and you can always remotely build/fix stuff while you're away on other planets

I made the mistake of leaving Nauvis too early, and my coal train got into a deadlock, killing the power. By that time I was on Gleba already, trying to figure it out from scratch.

Emotionally? It was damn scary! Gleba enemies kept evolving and I didn't have the resources to fend off their attacks. I rebuilt the harvesting towers countless times, letting the spores (pollution) die down each time...

But... Being able to overcome that was amazing! I managed to build a rocket, go back to Nauvis, fight off all biters that took possession of my real estate, and start sending coal shipments to Gleba for landmines. That really tipped the scales.

Right now I'm a few steps further. I built more space platforms to send emergency supplies where they are needed, and each planet has a Spidertron able to fix any emergencies that might pop up. Especially that last part is very comfortable.

So to relieve your anxiety, consider doing Gleba first so you can unlock Spidertron as a backup.

A careless forward looking attitude! Screw the old stuff! On to the new!

Biters attack because you attack them or they absorb too much pollution. Push the biters back so they are outside your pollution cloud

Now you only have to defend your pollution cloud from the biter expansion parties. Which are much smaller than attack parties.

Enough defenses around the base. Automatic production of everything in the defensive line. Bots. Many, many bots. Making sure the pollution cloud is not in the way of the biters.

Practice managing your base only through remote view, do everything through remote view. It's pretty good. You can do anything.

Roboports will provide radar coverage even without power. Robots will move very slowly even when powers out.

If you're worried about biters, make sure you have defense in depth, so you have time to respond if something goes wrong. I.e. Wall of lasers, behind that a wall of gun turrets and flamethrowers.

Before you leave the planet make sure your robo network is entirely self-contained, maybe a square, or a circle. So that none of your robots have to fly over enemy territory

Use alarms! Set them up for every base. Low fuel, low power, low iron, low ammo, etc, etc

You can remotely control vehicles from another planet. Get tanks set up with personal roboports and you can send them off to fight biters and repair your defenses.

The factoriopedia has information/briefs about what enemies, if any, to expect on other planets. Only some require combat.

Produce tons of roboports and bots so you can manage everything. Gleba gives you spidertron so you can clear stuff up at home and build outposts to expand. You could also go to vulcanus and get the artillery to clear up biters at home to expand.

Then you'll have no longer depend on personally being on Nauvis to manage it and can do it all remote and make you free no explore other worlds.