eBay's Time Away mode is a max of 30 days before you have to reset it.
If you end the listings eBay will store them on your ended listings page for 90 days before deleting them.
You can enable the out of stock setting.
https://www.ebay.com/help/selling/listings/creating-managing-listings/multiquantity-listings-listing...
Then change all your listing quantities from 1 to 0. They will remain active, but hidden from search because there's no stock. After 6 months of being out of stock eBay will end the listings and move them to your ended listings page.
They will reside on your ended listings page for 90 days before eBay deletes them. From your ended listings page you can relist with a quantity of 1 when you return - and don't forget to turn off the out of stock setting.
Keep in mind: during those 6 mos they will use up insertions each month. Because you said you'll be listing new items while away, you may not want to use up insertions for out of stock items. If that's the case you'd be better off subscribing to a third party listing tool which will give you the option to download your listings and store them offline for as long as you need.
A more cumbersome option is to end the listings, then relist and save in draft format. That will save them for 75 days, and you'll have to go in and revise the drafts to keep them available longer than 75 days. But - sometimes drafts go missing and frequently photos will disappear from drafts so you should have those stored offline to upload later.
Honestly, since you plan to list items from your second location while away, using a third party listing tool to store offline is going to be the easiest option. You can do a free one week trial and download your listings. Then when you return, subscribe to the tool for a month so you can upload those listings.
