It is strange to even contemplate this but I actually think Alex has done it.
He is a much more decorated combat athlete winning belts in multiple weight classes in two combat sports.
He has beat Israel 3 times and twice by stoppage.
Izzy knocked out Alex but in that fight Izzy was getting outclassed.
He moved up in weight class and won the belt and then defended the title.
He ko Strickland, the guy that Israel got beat badly by.
Unless Izzy does something spectacular like moving up in weight I do not see him touching the legacy of Alex.
mentions Izzy KO'd Alex but Izzy was getting out classed - meanwhile in reality the judges scorecard gave Izzy the first round.
And the golden bit
at the same time forgets Alex got destroyed so bad in the 2nd kickboxing fight, he had to be rescued when he was on the verge of being TKO'd by the hometown ref no less
and then the same thing in the 1st mma fight, but via the luck of the bell
But to answer your question, 1 on 1, nope hes not close to izzy's level - being "3-0" and still the underdog is a great proof point on this.
But on accomplishments, depends how you rate things. Paper glory champ, legit UFC champ in 2 divisions. 1 title defense.
Bashing on him cause he got near TKO'd and embarassed in front of his home crowd aside ( i mean being rescued by your hometown ref - shame), he is pretty close and should he continue to be dominant at 205 then yes.
Looking at what they have done:
You have long 185 dominance, 2x champ highlighted by knockouts of Costa, Whitakker and Pereira, with a war involving Gastellum. All on the most active schedule in a long time
But with some boring showings and a misstep vs Strickland
vs
Record rise to the top, 2 x division champ, highlights vs Izzy (ill count that last round comeback), Jiri, Hill and Strickland
But, Izzys son, fast tracked via Izzy, very questionable matches (always vs strikers) and right place right time (eg chaotic LHW division)
Depends on how you rate things, could be in front of Izzy now.