My plan: don't rely on the secrecy of anything encrypted now with RSA to remain secret in 20 years, and never use it for encrypting data-at-rest. Hell, Schneier already increased his PGP key size to 4096 bits, I don't think it's a stretch to think 2048 could be broken classically by USA-level actors in the not-too-distant future. But since you're not using RSA for data-at-rest, more for transient "messages", hopefully the value of anything intercepted and stored for 20 years will be relatively low.