#3 Adam Lewis
The likes of Ben Woodburn or Curtis Jones maybe the picks for the third spot in this list. However, with enough competition and backup for the positions that they play in, they might have to wait for some time more to get regular first-team football.
The position that Liverpool need a backup in is the left-back position and they can get the backup without spending big money in the transfer market by promoting young Adam Lewis to the senior team.
Lewis has made 85 appearances for the Liverpool youth sides, scoring 7 goals and assisting 23. He is a tireless full-back who likes to attack but does not forego his defensive duties. He is a lovely crosser of the ball and a brilliant free-kick taker which is demonstrated by his assist stats. He is also a strong tackler who can play as a left-back, left winger or as a central midfielder.
His versatility is an added bonus to his ability as a defender. He can be a good enough deputy to Andy Robertson and can be the next Alexander-Arnold, breaking through at a young age to become a world-class talent.
Thus Liverpool have a huge reservoir of young talent and they would be wise to invest in youth rather than spend money on new signings, especially when considering backups for regular starters.