Soooo, had a group start with pre gen characters and we finished the campaign and they loved it and wanted to play another arc with characters they all made. So they all made magic characters. In an attempt to keep the game fun and rolling forward I dont want to restrict them by using the literal dog poo out of hacking obstacles and drones but magic adversaries may not be as much of a challenge.
Just looking for suggestions. Any help is appreciated.

I had someone create a kind of anti-magic character for a game, but he never did make it to a session (the player, not the character). The character, IIRC, was an elf mystic skilled in Counterspelling & Banishing, and had adept powers to help with resisting magic, and other skills elsewhere. Knew no spells, had no skill in even summoning spirits, was just skilled in negating things magical.

The best weapon is knowledge. So check the magic rules properly (there should be a lot of corresponding topics here on DS. Try the search term "magic overpowered"), then you shouldn´t have much problems with your spellslingers.

Well, on the other hand, magic opponents could be way more of a challenge,
because you can make them more complex,
than what would be used against an ordinary runner group.
Wizard-duels can be fought out, and that is just pure awesome.
Imagine what a runner group which is only made up of mages, would be hired for.
Not your average corporate extraction.

Also, while you should of course know the rules in and out,
because one subsystem is played mainly,
do not plan everything while looking to the rules.
Magic leaves open a lot of opportunities for telling, as opposed to ruling.

You can leave a lot unexplained which would be a waste of time for more than half of the group,
if those were mundane.

In the Shadowrun fluff for magic, there is a lot of room for improvisation and interpretation.
Use that, because you will not get the chance as much with a normal group.

How about tailoring an artifacts-style campaign?
Steal from Indiana Jones, Tomb Raider and the overall genre and make them a university-funded group at the beck and call of some arcano-archaelogist.
Exotic locales, devious traps (not always to be overcome by magic), artifacts or access routes only accessible by magic, and so on. You can even play with heavily aspected background count at times, making the PCs weaker and their enemies so much more potent, in a way that they can only overcome them as a group effort.
Whip up some impromptu rules for rituals on the spot, linking everyone together by holding hands / using the same fetish / spilling their blood / etc.

The last campaign I ran had two mages, a phys ad and a rigger. We NPC'd a decker, which saved a lot of time and helped keep the game moving.
I love not having "optimal" groups. Old school shadowrun was like that. 2 gangers and ex wage mage trying to extract his girlfriend from the Aztechnology pyramid. A decker and his troll body guard trying to stop an assassination in Vegas. Whatever.
That's what contacts are for, and why they're worth the points. Rather than fill every possible need with the PC's, you hook a friend up with a job when you need muscle, or decking help, or a class A wheel man.