Regarding tires, the problem of flat spots can be reduced by inflating to the max pressure listed on the sidewall rather than the vehicle's recommended pressure. You will of course have to remember to bring them back down when taken out of storage, but they should be checked at that time anyway.
Has anyone used partsouq since the start of COVID-19? Did your order take longer than usual to arrive? The site has an update that indicates 3 to 4 days order processing. I wonder if shipping is also impacted.