Hi,
Yes, if you pass PL-200 or PL-400 you will earn Microsoft Certified: Power Platform Solution Architect Expert certification since you already passed PL-600. You must pass PL-200 or PL-400 within 1 year of passing PL-600. I recommend passing PL-200 or PL-400 within 1 month to avoid any issues.
Please click Accept Answer if the above was helpful.
Thanks.
-TP