Render test

main.go

package main

import (
	"strconv"
	"strings"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

var (
	a        fyne.App
	window   fyne.Window
	textArea *fyne.Container
)

func main() {
	a = app.New()
	window = a.NewWindow("Render Test")

	loading := widget.NewLabel("Loading content...")
	textArea = container.NewMax(container.NewVScroll(loading))

	reloadBtn := widget.NewButton("Reload", nil)
	reloadBtn.OnTapped = createRichText

	bottom := container.NewHBox(reloadBtn)
	main := container.NewBorder(nil, bottom, nil, nil, textArea)
	window.SetContent(main)

	createRichText()

	window.ShowAndRun()
}

func createRichText() {
	// create one RichText object per section
	objs := []fyne.CanvasObject{}
	for i := 0; i < 30; i++ {
		letter := rune('a') + rune(i%26)
		word := (string(letter)) + "text "
		paragraph := strings.Repeat(word, 100) + "\n"
		section := "## header " + strconv.Itoa(i+1) + "\n" + paragraph

		richText := widget.NewRichTextFromMarkdown(section)
		richText.Wrapping = fyne.TextWrapWord
		objs = append(objs, richText)
	}

	scroll := container.NewVScroll(container.NewVBox(objs...))
	textArea.Objects = []fyne.CanvasObject{scroll}
	textArea.Refresh()
}

If you need an icon for testing, here it is: