Hi Nihal,
The From Address (sender email address) can be impactful on the whole domain's sender reputation (for deliverability/"spam score"), not just the single host email address/alias. The From (sender name) doesn't really have an impact so the host name won't make a difference. I have seen in the past that using an individual person's name in the from address & name - that the recipient recognizes - may lead to a higher open and engagement rate as it seems more personal than a generic marketing alias like marketing@example.com.
But more importantly: What is the nature of the large contact list you will be sending the invite emails to? If they are engaged with your marketing and content and opted in to receive invites, that would generally have a positive or neutral impact on deliverability, even if the list is large. However, if the list is old, unengaged and/or you aren't sure if they provided consent to receive your emails, that could be very risky for your deliverability. It also matters whether you regularly send emails to this list or if this is one of the first emails you're sending from Marketo. If the latter, you may want to break up the recipient list into smaller sends to test out the impact.
Cheers,
Beth Massura
2022 Adobe Marketo Engage Champion