Square cube law means smaller satellites care less about g-forces. People shot vacuum tubes out of artillery shells as part of proximity fuses and they would survive just fine.

A cellphone experiences higher peak acceleration when hitting a floor when falling off a table but they are generally fine. So yes some sats would need modifications, but not necessarily significant ones and you can trivially test those conditions prior to launch. A Starlink competitor would happily design for such if it reduced their launch costs by 90%.

First of all, all sats need modification. Things like reaction wheels simply wont work the same. Usually launch vehicle selection is done well after engineering on the project is along quite a bit. SpinLaunch basically requires that you make a decision to be SpinLaunch compatible as soon as you start. And that will force you to use some of their parts.

This simply isn't something that anybody would do unless there is a huge benefit to it. Spin Launch still requires a rocket, and one that will likely not be reusable one anytime soon. So the idea that its going to massively reduce cost is a fantasy.

To even have any cost saving at all they need a huge number of launches. There simply isn't a market for that many tiny sats. There is a reason all the constellations have moved to larger sats that are not SpinLaunch compatible. Micro launch is a tiny market and companies like SpinLaunch are just lying to their investors, just like Astra did.

If we are looking at things like consumables, it would take 500 SpinLaunch launches and that doesn't even match a single Starship launch. How anybody could think this would be cheaper is beyond me.