Depending on how much you trust your party (or vice-versa), you can just run distributed across their mesh inserts. RAW you only need a minimum of two devices to count as "distributed" and reap all the benefits (and downsides) thereof, so technically you can be running without aptitude limits anywhere that two or more party members are in mesh contact. Or one party member with a spare ecto on their belt (which can be hardwired with a fiber-optic cable, if you have a need for radio silence). This is of course counting on the fact that the inserts/ectos in question can run you at aptitude 20 on their own (they're "personal computers"), in order to argue that if one can run you alone then surely two can run you together (to avoid "minimal processing environment" rules). This is before considering your party is likely carrying several devices that could count as "peripherals", and contribute to your distributed network if you need to eke out some more processing power. Granted, it's an argument that is likely to raise the GM's eyebrows and it substantially amplifies the risk if a party member goes Exsurgent (since if they're part of your network at the time they can infect you, and then you infect everyone else you're running on). Although if you have proper boundaries and permissions in place you could probably ensure that getting you would still require a hacking attempt, which you could respond to by jettisoning the offending party member from the network and killing their comms.

It's super cheap in the rules, but you can just hardwire in a bunch of devices to run "distributed", basically a fake server. I think the latter numbers you came up with are fine. Higher aptitude caps aren't so powerful in or out of setting that they should be that expensive.