It is unlikely that these Marders will go to Ukraine, and it is not Scholz's fault that this is so. People that are criticising Scholz for this either do not know the facts, or do know the facts and are seeking to score political points off Scholz - heck his party wasn't even in power during the decade+ these Marders became irreperably unserviceable.
All the few hundred Marders IFV that are fit for use are actually operational in peace keeping operations and such like. The thousand or so that are in storage are better described as scrap metal. They have been plundered for spare parts to keep the operational ones going. Better to start again with a newbuild vehicle, which is actually the German aim although that will not be available in time to help Ukraine. This has been a longrunning issue in the German military, it was bad that the Germans couldn't really fulfill their NATO and EU responsibilities for high readiness forces. I have been reading various reports on this for many years.
The older Leapord 1 MBT sound as if they are not in much better condition. I doubt they could be put in a fit state to go to Ukraine this year. Same reasons. And the operational Leapord 2 MBT are pretty scarce. You could say the same for the older UK Challenger MBTs, and for much the same reasons I'm not sure the UK would want to release the upgraded ones (which in any case are due to start cycling through their own next upgrade programme). The French have the same issue with the Leclerc MBTs. To be honest all Western IFV and MBT next-generation vehicle programmess have been going round in circles for a couple of decades due to the inability to get a design solution that adequately closed the move-fight-armour equation, and watching the results from Ukraine may make that even worse (for very political reasons, I digress).
In any case putting any of these Western MBTs into Ukraine would require a huge logistical and retraining effort that should not be underestimated. The only ones that are available in sufficient numbers are the M1 Abrams. The French, German, and British MBT fleets are simply too small to b eworth the effort distracting the Ukraine with.
Far better to focus on moving the stocks of ex-Soviet MBTs and IFVs. And artillery, lots of it, then more. And get them those planes - the ex-Soviet ones for now. And (being realistic) a shed load of F-16s for follow on use.
[EDIT - update, I have just read that Scholz has pretty much confirmed my views on the Marders. It is worth reading the rest of that as Scholz makes a number of other valid points
Germany will stop importing Russian gas ‘very soon’, says Olaf Scholz]