It sounds like we’ve been thinking along similar lines, and I’ll be curious about your success. After having early disappointments this year with pepper germination, I’m sowing in a new set today, along with tomatoes (yesterday). Most of the seeds are on the oldish (4 years) to definitely old (10 years) side, and I am realizing I might wish to up my game accordingly.
For the peppers, I scarified for the first time. This was more laborious than I realized. Grabbing and then running each seed on sand paper individually is painstaking work, and frustratingly slow, even for someone with small fingers like myself. I am wondering if there’s a faster way to do it.
For both the pepper and tomatoes, I did a presoak of hydrogen peroxide, just a short soak (10 minutes). It occurred to me that the harshness of peroxide might damage fragile inner seed tissue. The internet seems to think it’s fine to soak in peroxide after scarifying, but the internet has led me astray many times. So we’ll see.
Then the seeds got transferred to a chamomile / green tea / liquid kelp liquid I made ahead. I brewed tea at roughly double strength and added liquid kelp at a rate of one teaspoon per 8oz. I’ve seen the scientific studies on kelp and I’m convinced; apparently it has hormone-related growth-producing properties. I’m less convinced about chamomile and the black tea (I used green because it is what I had), but many swear by both. Chamomile supposedly helps prevent damping off and the astringent tea supposedly helps break down the seed coat. Realizing now this may be entirely redundant with scarifying I did on the pepper seeds. But maybe it would help with the tomatoes. Hopefully it won’t hurt.
The tomatoes soaked for a few hours, I left the pepper seeds soaking overnight. Just before sowing, I sprinkled a little mycorrhizae powder into the tea blend that each batch of seeds was soaking in. I strained out the seeds, sowed them, and then gently drizzled the tea blend on top to water it in.
One thing I learned to do that dramatically sped up my work is that it helps tremendously to dry seeds on a paper towel before attempting to sow them. Otherwise they just stick to your fingers or tools and it’s very frustrating.
I also adjusted my growth setup, which I believe was too hot (learned this thanks to folks chiming in on this thread). Have things running a little cooler now (hi 70s to low 80s).
I have to be honest, by the end of all this I was starting to feel a little silly, like maybe I am overdoing it. Or maybe there’s a magical ritual I still have to perform that will make the difference 
. I’m really not sure if I’ll ever go thru all this for fresh seeds, but if it proves effective, it might be worth it for older seeds of a beloved variety.
EDIT: I am also wondering about the wisdom of germinating old seed in the first place. I’ve seen reports from folks saying that the plants that they grew from old seed were less vigorous overall. I also wonder if the genes can get damaged with aging, which would be relevant if one is propagating to retain a particular strain into the future. This is beyond my knowledge but would be so curious if folks have any thoughts on this
