$20k worth of internet related work is more than enough to start taking tax deductions for (presumably) your work from home.
I'm not a tax agent, tax preparer, or anything of the sort, but:
- Home office. Totally worth the deduction. You can deduct a portion of your rent/mortgage and utilities (electric, mostly) for business use. It's an "audit risk," as you note, but if you can justify it, there's no real problem. Not taking deductions because they might trigger an audit is silly, if you can actually justify and defend the deduction.
- Your connectivity is absolutely related. You can deduct a lot of that, especially if you have extra connections solely for business purposes. I intend to deduct 100% of one of my internet connections this year (I have 2 for reliability reasons since I'm rural and work on the internet) - the only reason I have that second one is for business purposes. I can deal with a slightly flaky connection for personal use, but "Sorry, can't jump on the conference bridge, internet is acting up" isn't really acceptable except in emergencies.
- Technology and office environment upgrades. A good chair, good keyboards, etc. I don't think twice about buying that sort of stuff and deducting it, if I don't already have it.
Now, all that said, "buy it for the tax deduction" is silly if you don't actually need it. As is pointed out below, "Spending a dollar to save $0.45" isn't an efficient way to save money.
Addressing other points brought up:
I've got some purchases planned: new cellphone (mine is 3 years old) - thinking Note 8 for $1k, new laptop (mine is 2 years old) - thinking Surface Pro for $2k, new tablet (my tablet is 5 years old) - thinking current gen tablet for around $300 or so.
$1k for a phone is a bit excessive (especially for Android), IMO. A new Project Fi device will get you Sprint & T-Mobile connectivity for a good bit less than a Samsung Bloaty McBloatware (yes, I'm biased against Samsung).
For the laptop, what are you doing that would justify the upgrade? I've got some hardware that's newer, some that's older, and the older stuff still works for most of what I'm doing. I don't generally upgrade hardware until I'm either out of OS support (security updates/feature updates) or it no longer does what I need (my old Macbook Pro can't run a few VMs at once, which is a business need for me that my iMac serves). Tablet is probably fine to upgrade if you actually use it for business.
I agree with the "cast a wide net, but make sure you can reasonably defend it." A huge TV in your living room "for video conferencing" that you never use? Probably not legit. However, if you do a lot of video conferencing, a wall mounted monitor and good camera in your office area is totally reasonable. It just depends on what you do.
For me, I don't mind buying new tools related to my work (battery rebuilds, small electronics design) - and I'm usually going to buy more than I strictly need at the moment, simply so I don't have to buy it again. I've got a 50k count bench voltmeter/ammeter and a good 100MHz 4 channel scope with 16 logic analyzer channels because that's going to hold me for a long, long while as I increase my skills and design work (the scope needs to be fast for doing transient analysis, as undamped transients ringing will fry power transistors in a hurry).