Or, go for mechanized doctrine and use Rifleman on WC51 to harass the opponent. OKW has weak early AT.
Since the complain is about team game, this is bad advise though. Any half-brained axis player would put two or more atgun/at infantry behind to cover the elefant, and waits for USF tank to move into killzone.
You can argue smoke, but smoke does not cover every directions, and it work both ways. It will, however, at least allow USF player to retreat from killzone, but with casualty.
The best thing USF can do is use calliope to clear out these atgun. But unfortunately, calliope is locked behind commander...
Rifle Doctrine comes with rifle flare and 120mu phosphorus barrage. In large team game you can also ask a mate to use arty on them.
Anyway, I'm not going to argue that USF have easy time late game vs Jagt or Elef, just that 2 or 3 Jacksons aren't going to counter an Elef or a Jagt of an half-brained player (the same as yours). On the mean time 3 Jacksons are going to suck you a lot of manpower and popcap for 0 IA power and let you subject to infantry rush.
4 Shermans (2 EZ8s and 2 regulars) will repel any infantry rush, soak more damage vs the jagt and elef and if you see an opportunity to take off the big cat by flanking it will do the job as well as 3 Jacksons because:
1- close distance = less chance to be bounced
2- Smoke = can disable an unseen Atgun
3- More life so more chance to survive
4- more IA power so possible to clean other AT source on the mean time or wipe squads around.
Shermans are also hitting the field much earlier and you can have two of them far before any heavy TD hit the field. Use them as infantry killer, your opponent will have harder time to keep the line and call a a Jagt or Elef in time.