For e.g. if you got dogecoin and 14 other cryptos, and you want to send doge, just import the seed it in any self custodial dogecoin wallet and you're done. Do the same for rest of the crypto coins, i.e., import the same seed in their respective compatible wallets.
I would only suggest importing a seed that's been generated in a safer system such as a hardware wallet into a software wallet if it's an emergency. Most of the times though, it's not an emergency. If someone losses their hardware wallet or it breaks, they get afraid they will lose access to their coins and want to reassure themselves by recovering them asap. You are just minimizing the security of your seed that way and making it potentially vulnerable as well because it's been used with a hot wallet.
Importing your hardware wallet seed into one software is bad enough. Doing it in 15 different ones just increases potential attack vectors. For your crypto to get stolen, either one of those 15 hot wallets need to mess something up. Compare it to having a secret, telling that secret to one person and revealing it to 15 people.
If you can't use your current hardware wallet any longer, get one from another brand and restore your wallets from your backup seed. Generate new seeds and wallets on the new one if you lost trust in the old device and gradually move your coins to the new one.