Rebuilding your example and running it like suggested by J.D. it seems that with your code everything is just allright.
There was just one missing declaration in your for-loop, but the code works just fine and also the loading-time is absolutely ok…
const start = Date.now();
console.log('START', start);
$w.onReady(()=>{console.log('$w - start (ms)', Date.now() - start);
let sentence1 = $w('#txt1');
let sentence2 = $w('#txt2');
let sentence3 = $w('#txt3');
let sentence4 = $w('#txt4');
let floatDir = {
"direction": "left"
};
let floatEsq = {
"direction": "right"
};
for (var i=0;i<100;i++){
setTimeout(()=>{sentence1.hide('float',floatDir)},i*14000+5500)
setTimeout(()=>{sentence2.hide('float',floatEsq)},i*14000+5500)
setTimeout(()=>{sentence3.show('float',floatEsq)},i*14000+7000)
setTimeout(()=>{sentence4.show('float',floatDir)},i*14000+7000)
setTimeout(()=>{sentence3.hide('float',floatDir)},i*14000+12500)
setTimeout(()=>{sentence4.hide('float',floatEsq)},i*14000+12500)
setTimeout(()=>{sentence1.show('float',floatEsq)},i*14000+13500)
setTimeout(()=>{sentence2.show('float',floatDir)},i*14000+13500)
}
});

I would say 62-milliseconds for a loding is - → OK.
I would suggest you to read this one first, perhaps you have such a problem…