Spammers joining site

You have hundreds of new users being created every day that never check one movie or favorite or anything and their usernames are a jibberish mix of letters and numbers and are sequential like these.
(They all signed up in one single day)
sydn984ll
sydn018jg
sydn473jk
block890jy
sydn601dy
sydn682dx
block767ig
sydn763wg
block034qx
sydn750ci
sydn127jb
block320fo
sydn715ve
sydn602hz
sydn682pe
block166ru
block173tx
sydn822nz
block494mb
sydn426xh
sydn904ma
sydn840vo
sydn561ww
sydn276iy
sydn684ug
sydn002ed
sydn117nq
3oliviae2923wM5
8jordane15100ra1
6jordane3923fg6
3alicec68100hr1
5jasminee513hg3
5jordane512gh1
9taylorc6285eh5
4jordane5723tp3
5milae83100fr1
9charlottee9322rh4
1andrewe65100th2
1andrewc771tc1
4avae1322ro5
7miae792wo6
1avac7122fL3
8adriane962rp4
7giannae5322fg1
4miae2491hc9
8jasminee722ra1
4miae8323yN1
7giannac542ec0
3evanc8523wg0
1harperc753rg4
3lydiae821hb6
4harpere231yr5
6madisonc53100rp1
4camilae84100eM4
4carolinee8522wM1
3charlottee59100te5
8oliviac38100tc2
1adriane472wc9
6emmae6285th5
4audreyc212tc9
2emmae631rb3
7milac791ra6
7camilac952yp9
2sophiec5285rb6
3harperc6223fb5
6oliviae7623yc7
1jasminec4922tM3
5avac911yh2
7lydiae243fg4
6adriane9291rB2
4camilae91100yp1
9gabriellac8422wL4
3charlottec8791rM1
2milae252hp7
5claudiac6822rg6
5evanc5191ec1
9claudiae341fr6
2carolinee532gh7
8gabriellae9423yg2
6madisone77100tN1
7gabriellac132tN9
5alicee6585eN7
9harperc241ra4
8jasminee3285eN1
4claudiae86100gg2
4emmac3723wb7
4alicee32100wc6
They are going to ruin the site, fill up the database, and break things for everyone else.
You should stop them by blocking them from being able to sign up. Maybe you need a new verification method during signup that’s better than what you have now?