Too many seedlings - what to do?

[SleepyHedgehog]

I chucked a load of cosmos and another annual (lost the pack) into a 30cm diameter pot. The seeds were very old but turns out the germination rate has been great, and now the pot is waaaay too full. Ideally I want to keep the seedlings and grow them on elsewhere.
Not sure which plan of action to take.

Do I divide the pot in half and let them spread over 2 pots? Try to remove individual plants but risk killing them all in the process? Thin them and accept they cant all live. Leave it and sit in a puddle of regret watching them compete in the stuffed pot?

I would thin the weakest out now, then pot the remaining ones out when a bit bigger.

Thin them and just accept it. If you split into two by just dividing, they will still be too close together and crowded.
Maybe split and thin though if you have loads.

Thanks both, time to try my hand at thinning!

I pick out one or two easily separable big ones and pot them up, then divide the rest into clumps, as small as possible taking into account my level of patience at the time