There's a lot that can be done to help in terms of preventing jamming and detecting, and it mostly involves a tradeoff with bandwidth/latency. The simple approach to evade jamming is to decrease the FEC (forward error correction) ratio (meaning using more bandwidth to send each bit, simply put) and increase retransmit backoff and any timeouts, to make detection harder you would send packets from the user's dish less frequently and with random delay (increasing upstream latency).

Both could be countered by a sophisticated adversary, but the Russian troops may be a little preoccupied at the moment, and their EW teams are probably going to focus on Bayraktar before Starlink...

Starlink have already enabled "Roaming" for Ukraine which involves similar tradeoffs: https://www.youtube.com/watch?v=8PDVURcvWeg (in fact I wouldn't be surprised if the changes enabled for roaming also improve jamming resilience)