Uhhhh difference between linked and merged? I had PC account originally, then ported it to Switch when there was one-time chance. Now the Switch account overwritten PC account and they're shown as connected on account page.
So, I had 5 regal Aya on Switch already. I've logged into Switch account on the website, saw that you can buy Aya from warframe.com. I've bought it (3 aya + 200 platinum), got the message from Ordis - but I still have only 5 Aya on my Switch account.