It's too much of a risk for only 5× Chase UR points per $1. It would be safer to buy plastic Home Depot GCs in-store at Staples rather than buying plastic or digital cards online. It is best if you could get $500 Home Depot cards but they probably don't go up that high — it will be a hassle to manage so many cards. With Lowe's, you are actually limited to redeeming 5 gift cards per order online (don't know about HD).
I think this would only be worthwhile if they were offering 10% off which Staples and other retailers occasionally offer for Lowe's GCs. Staples usually does an in-store/online sale for $90 for $100 Lowe's GCs in-store and online around December... there is a limit online but you could go to multiple stores to buy $20K+ although it will say Limit 1 in-store. Some stores may let you buy more.
As for eBay, they commonly do $90 for $100 Lowe's GCs, but the limit is 3 or 5 cards and you will quickly get blacklisted if you try to use multiple accounts to buy extras.
You would probably be better off just using a 2% cashback credit card at HD instead of tying your money up, having to administer and manage record-keeping for the GCs, being exposed to potential fraud, and not having the buyer protections that you would enjoy if you paid for your home renovation merchandise directly with credit cards instead of Home Depot gift cards.