Yes, it would bottleneck in modern games. That's 2013 Ivy Bridge CPU. Had same CPU myself back awhile. Things have come along quite a bit in IPC, frequency, as well as Core/Thread count since then. Your CPU is 4 core/4thread which in AAA titles and those utilizing Ray-Tracing technology, you will be limiting your performance.
Yes, it will. By a lot. From 30% to 60% depending on game at 1080p.
Even a RX570 is bottlenecked by a 4/4 Sandry Bridge/Ivy Bridge. Specially at stock. I had a Core i5 2500k@4.4Ghz until last month and mine RX470 was subutilized by 30% at some games. Very few I had 100% GPU usage.
You should only buy a RTX card if you're planning to buy a new RIG (at least Ryzen 1600/2600+B350+2666Mhz). If you're not, stick with a RX570 or the new RX5500 knowing that you will have a bottleneck already.
Coffee Lake, Coffee Lake Refresh, and the newer AMD Ryzen platform, namely the newest Zen 2 3000 series are all great choices in modern games. Shouldn't bebottleneck in any modern title if you stick with models 6-core/12-thread or 8 cores. Plenty of speed for now and down the road. All depends on budget and your specific needs, as all these require a total platform overhaul.
Yeah any thing with more than 4c 8T ryzen 2nd gen would be preferred over 1st. I personally am running an i7 2600k at 4.9 ghz, I'm planning to upgrade to ryzen within a week or 2
Yes, modern Intel i7 and up, or if you choose AMD route, 3000 series preferably. These are if your budget allows. Plenty of articles out there for comparisons in games.
Yeah any thing with more than 4c 8T ryzen 2nd gen would be preferred over 1st. I personally am running an i7 2600k at 4.9 ghz, I'm planning to upgrade to ryzen within a week or 2
No, it doesn't have to be an i7. Technically, modern i5s are 6-core. That said, Ryzen is really taking off in the price/performance ratio and are a great value at pretty much all the price points. Having both modern Intel and Ryzen, I can vouch for both being great choices whichever path you take. I would avoid a 4-core or even 4-core/8-thread if buying brand new. They are showing their age these days in demanding games and other software capable of utilizing more cores.