Retirement tax questions

Thanks guys!
one last question (i think/hope...)
My taxable gains (besides salary) are INT, or DEV, not even close to the 15K i lost...
If I declare the 15K lost on 2024 form, will it carry over to next years declarations too?
(lets say I gain 2K every year - will declaring now 15K will automatically offset the gain in the next 7-8 years, or that is the meaning of "breaking it up, up to 3K a year" - and each year I'll declare enough to offset that year gains back to 0? Is there an up-side to declare now the whole 15K this year, even if I didn't had capital gain as 15K?)

thanks!