Hello; While there is likely a concentration of the beneficial bacteria (bb) in the media of a filter, there is also a population of bb on other surfaces of the tank. This should include the hard surfaces, the plants, substrate and so on.
Assuming the tank was established and stable there will likely be some impact from the loss of the bb in the faulty filter. The impact can likely be mitigated a bit by no or little feeding for a few days. This should reduce the additional ammonia from possible excess food and the acssociated decay as well as potentially reduce the biological waste from the fish during the fast. The other bb colonies will reproduce rapidly and have likely already begun to do so since the filter quit two days ago.
Water changes should help remove and dilute the potential spike of ammonia.
I have searched about the impact of live plants on ammonia levels. As best I can gather there seems to be some aid in removing ammonia with the addition of live plants. It is unclear as to how much ammonia plants can take up directly but some seem to feel they do take up an ammount. A bunch of hornwort or some similar plants should not hurt at any rate.
The bb in the filter may be much reduced or dead in the failed filter and there is a risk from simply tutning it back on. I have read posts about this. A member had an external filter be off for several days. When it was simply turned back on the accumulated decay products flooded into the tank and spoiled the water quality causing the death of the fish. It seems that the filter will likely need to be cleaned out and established with clean media.
Good luck
