I have been running own mail server for over 10 years already, if you follow the standards (proper SPF/DKIM/DMARC records) - it rarely becomes a problem, rarely corp domains hosted on gmail push emails to spam, but overall 99.9% of emails are delivered correctly.
Try any and keep blogging. Once you progress in making your content, you will better understand your needs, which will assist in a better decision: either keep current platform or pick a better one for your blogging needs.
1. Stick with DDR4 systems, DDR3 are much slower.
2. Used to have both 1U and 2U servers at home, as people mentioned they are pretty loud, try to avoid
3. Regular commodity tower case with slots for 120 fans is best in terms of loudness/cooling capabilities
4. Try build something on commodity hardware pieces - would be easier to sell it away once you want to get rid of it.
Very surprised to see just few comments mentioning EPUB, which is IMO is much more suitable for document-centric approach. An open standard with freely available[1] specification and never had any problems with EPUBs on PC, tablets and phones.
I remember Toshiba AC100 back in 2011 (afair) with tegra cpu and 3G modem weighting about 800 grams. Originally shipped with Android without marketplace, became more or less usable after installing Ubuntu on it.
They really could win a niche of ultraportable laptops.