SVG 'set' animation not looping as expected - svg

Question

I have a fairly simple SVG with 2 text elements. I want them to switch every 2 seconds (e.g. "2019", wait 2 seconds, "2020", wait 2 seconds, repeat forever).
For the life of me, nothing happens after the first "2019" is shown (e.g 2019 shows, then never goes away and 2020 never appears). If I change the show2019 begin to "3s;hide2020.end" it doesn't show up for 3 seconds, as expected, but still doesn't continue.
<?xml version="1.0" encoding="utf-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="49" height="64">
<rect x="0" y="0" width="49" height="64" rx="5" ry="5" stroke="#F00" fill="#FFF" stroke-width="1" />
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" fill="#F00">
<tspan x="50%" y="1em">Check</tspan>
<tspan x="50%" y="2em">Terms</tspan>
<tspan x="50%" y="3em">for</tspan>
</text>
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" font-weight="bold" fill="#F00" visibility="hidden">
<tspan x="50%" y="4.5em">2019</tspan>
<set id="show2019" attributeName="visibility" to="visible" dur="2s" repeatCount="123456" begin="0s;hide2020.end" />
<set id="hide2019" attributeName="visibility" to="hidden" dur="2s" repeatCount="123456" begin="show2019.end + 2s" />
</text>
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" font-weight="bold" fill="#F00" visibility="hidden">
<tspan x="50%" y="4.5em">2020</tspan>
<set id="show2020" attributeName="visibility" to="visible"dur="2s" repeatCount="123456" begin="hide2019.end" />
<set id="hide2020" attributeName="visibility" to="hidden" dur="2s" repeatCount="123456" begin="show2020.end + 2s" />
</text>
</svg>
CodePen

Answer 1

Well, I bring you an even nicer solution which resembles a path transformation. Instead of using set...attributeName I used animate...attributeName which allows you to do the same with better look and less code.
See the code here:
<svg xmlns="http://www.w3.org/2000/svg" width="49" height="64">
<rect x="0" y="0" width="49" height="64" rx="5" ry="5" stroke="#F00" fill="#FFF" stroke-width="1" />
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" fill="#F00">
<tspan x="50%" y="1em">Check</tspan>
<tspan x="50%" y="2em">Terms</tspan>
<tspan x="50%" y="3em">for</tspan>
</text>
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" font-weight="bold" fill="#F00" opacity="1">
<tspan x="50%" y="4.5em">2019</tspan>
<animate attributeName="opacity" from="1" to="0" begin="0s" dur="3s" values="0;1;0" calcMode="linear" repeatCount="indefinite"/>
</text>
<text x="50%" text-anchor="middle" font-family="sans-serif" font-size="9pt" font-weight="bold" fill="#F00" opacity="1">
<tspan x="50%" y="4.5em">2020</tspan>
<animate attributeName="opacity" from="0" to="1" begin="0s" dur="3s" values="1;0;1" calcMode="linear" repeatCount="indefinite"/>
</text>
</svg>
If you play around with the start duration and values can just adjust it as much as to meet your needs.