General

You can also get the Dark Critical Ring in the Reboot Coin Shop that increases your Crit Rate by 15%. It is 2500 coins though, so it's up to you.

There're many other ways to reach 100% critical without spending your hyper stat points. Try to do those ways first before spending your hyper stat points since you can put them on other useful things.

Something not mentioned yet is unique inner ability/legendary which can possibly get you %critical if you're very lucky. I have yet to see the line myself but the fact that the line's a possibility is worth mentioning.

Phantom 210 link wasn't too bad until SDH nerf. But yeah I guess you could get try to get crit % on your soul too.

7% from BT Link lv120.
15% from Phantom Link lv120.
4% from Marksman S-Rank Card.

This puts you at 91%. Use hyper crit to fill up the rest.

Here's how I did it:
your currently at 65
10% from level 210 bt
15% from level 120 phantom
5% from hyper skill se crit
5% from hyper stat
this would bring you to 100%. replace 3% from bt with hyper stat. I can confirm level 3 link skills are NOT Worth it.

Hyper Stats (1% - 15%)
Phantom Link Skill (5/10/15%)
Marksman Character Card (1/2/3/4%)
Inner Ability (1% ~ 30%)
Potential Lines (Weapon / Secondary / Emblem)

You can raise the hyper stat to raise your crit level
1) click stat> Look at bottom left corner> click hyper stat> raise crit

which server?