I include the HTML tags because anyone, at the senior level, doing WP also does HTML and you can always do nesting effortlessly in HTML!
Understand I wrote the 1st 3 books for the internet & was also SE Region Print Support for IBM, so I have been in WordProcessing since 1985. I started with PC WP in 1985 with WORDSCRIPT, then migrated to WORDPRESS, 1987-1988, then MS Word in 1988, & While at General Dynamics 1985-1992, wrote the IBM GML to SGML translator!
The concept of lists is very different in HTML and ODF.
In HTML, a list is a single-level construct of the form:
<ol>
<li> …</li>
<li>as many "li" as you need</li>
</ol>
or the same with ol replaced by ul.
Basically it is single-level. Multi-level lists are created by writing a full single-level construct in the paylod od one <li>. These nested list are independent from each other.
In ODF, every list is 10-level by construction. The equivalent element to ol or ul is a list style. You turn a “standard” paragraph into a list item by applying a list style to it. You can event make this systematic by attaching the list style to the paragraph style.
When you want a higher-level item, you press Tab at the very start of the item to promote it to higher level. To demote it to lower level, press Shift+Tab in the same position.
The list counter is entirely managed by the list style. Since the list style is aware of the level change, it generates the correct number without needing user interaction.
Consequently, there is no point in trying to “reset” numbering.
Rest numbering is only necessary when you create another occurrence of a list of the same “type” (a list “type” is characterised by the list style).
Don’t trust Format>Bullet & Numbering (or the equivalent toolbar buttons). This is a feeble compatibility attempt at providing a temporary convenience to M$ Word switchers, not yet aware of the more “polished” features through styles. The menu command is a “one-size-fits-all” service. It uses twisted heuristics to guess where a list begins and where it stops, mainly relying on editing order (then when you edit your document in later sessions, you may get really unexpected and surprising results).
The list style feature is really powerful and versatile, allowing to create formatting impossible to achieve both in HTML and DOCX, like intermixed independent lists. However, it is difficult to use it until you have a clear idea of the ODF list concept/definition. I remind you the key factor: a list is defined by a list style. A list style is nothing more than a tag in some way.