Rulings
Q1: If my Digimon has an effect "When Digivolving Blitz." but is not currently activating the effect of Blitz. Is it possible to attack my opponent's unsuspended Digimon?
No, the effect requires you to be currently attacking with Blitz.
Data Sources
EN
Official English Card Listworld.digimoncard.com
Lv.6 ZeigGreymon BT5-017 U Mega | Virus | Cyborg [When Digivolving] <Blitz> (This Digimon can attack when your opponent has 1 or more memory.) --- Inherited: [Your Turn] When this Digimon attacks with <Blitz>, it can also attack your opponent's unsuspended Digimon.
A
Official English (Asia) Card Listen.digimoncard.com
Lv.6 ZeigGreymon BT5-017 U Mega | Virus | Cyborg [When Digivolving] <Blitz> (This Digimon can attack when your opponent has 1 or more memory.) --- Inherited: [Your Turn] When this Digimon attacks with <Blitz>, it can also attack your opponent's unsuspended Digimon.
W
DCG Wikidigimoncardgame.fandom.com
Lv.6 ZeigGreymon BT5-017 U Mega | Virus | Cyborg [When Digivolving] <Blitz>. --- Inherited: [Your Turn] When this Digimon attacks with <Blitz>, it can also attack your opponent's unsuspended Digimon.
JP
Official Japanese Card Listdigimoncard.com
Lv.6 ジークグレイモン BT5-017 U 究極体 | ウィルス種 | サイボーグ型 【進化時】≪進撃≫（メモリーが相手側の1以上のとき、このデジモンはアタックできる） --- Inherited: 【自分のターン】このデジモンが≪進撃≫でアタックするとき、アクティブ状態の相手のデジモンにもアタックできる。