Is it really a 7 year itch or is that divorce screwing with your finances? I assume you have child support payments here.
In your situation, all of three choices (except a modification to the second) are completely stupid from a financial perspective. Sell the F30, use the money to buy a cheap used Corolla with cash, then buy whatever new BMW you want when the child support payments end.
I’m saying that as a young guy (late 20s) with a net worth in the top 10% of his age bracket and a fully paid off classic BMW that got bidded up to crazy money on an auction website. If I was divorced like you I wouldn’t even think of owning cars like this
Get another E46 while they’re still cheap. In a few years they’re going to be classics and start spiking in price