…のも無理 (は) ない => It's natural for... N3
Evaluate
のも無理もない => (to be) natural,(to be) understandable N3
Evaluate
一体 => …the heck; …in the world; …on earth N3
~のは…ぐらいのものだ => only (emphasis) N1
Limit
くらいの => Approximate~ N3
Emphasis on degree
いつかの ... => Previously N4
Time
…の…ないの => thinking whether or not to do something... N2
Position, perspective
というのは => because N2
…からいいようなものの => It’s a good thing that… this time… N1
Criticize
どのくらい => how long N5
... というのは => It means... N3
Explain
ぐらいのものだ => Only A N1
(Not)only , (Not) even